Have you heard of glow-in-the-dark petunias? Did you hear about them but assume they were some kind of trick or joke? Well, they're here, and they're very real! And you can own one today.

Meet "Firefly," the first commercially available glow-in-the-dark petunia. Developed by the company Light Bio, it hit the market in 2024. A breakthrough in synthetic biology, it really, truly does glow in the dark. Let's take a closer look.

What is the Firefly Petunia?

The Firefly Petunia is the world’s first commercially available bioluminescent plant. You may have seen other "glow-in-the-dark" plants that are actually just sprayed with phosphorescent paint. The Firefly petunia, however, glows entirely on its own through natural metabolic processes.

As anyone growing petunias will tell you, they don't normally glow in the dark. But scientists at Light Bio genetically engineered this variety, integrating genes from the bioluminescent mushroom Neonothopanus nambi into the petunia’s DNA.

The result is a soft, ethereal greenish glow that emanates from the plant’s flowers, stems, and new growth. During the day, the Firefly Petunia looks like a standard, healthy white petunia. But as the sun sets, it transforms into a living lantern, with the brightest light concentrated in the young buds and growing tips.

Where Can You Buy It?

You can't get a Firefly petunia just anywhere, and since it's a bioengineered organism, its sale is currently limited to live plants.

You can buy direct from the source on Light Bio's website. Also, if you shop through the site, you can get access to the Trial Pink Petunia, which is supposed to have "2 to 3 times the growing power" of the regular white variety. And it's pink!

Firefly petunias are also available from these authorized sellers:

The Magic of the Glow

To get the most out of your Firefly Petunia, view it in a completely dark room. The human eye needs about 5 to 10 minutes to adjust to the darkness before the subtle, moonlight-like glow becomes fully visible. Avoid placing it near streetlights or bright nightlights, as light pollution will wash out the natural bioluminescence.

How to Care for a Firefly Petunia

Firefly petunias may be a little science-fictiony, but they're actually very easy to care for and can be treated just like any other petunia. Keep in mind that the healthier the plant is, the brighter its glow will be.

Light

Firefly Petunias thrive in full sun – they need at least 6-10 hours of direct light to keep up the energy needed for bioluminescence. If you're growing yours indoors, be sure to put it in a bright, south-facing window. If it's not getting enough light from the sun, supplement with a full-spectrum LED grow light.

Water and Soil

Petunias like well-draining soil that's consistently moist but never soggy. If the top inch (2.5 cm) of soil feels dry to the touch, it's time to water.

Fertilizer

Glowing is hard work, and Firefly petunias need to take in a lot of nutrients to keep it up. To keep the glow at its maximum intensity, apply a balanced fertilizer (like 20-20-20) every 1–2 weeks during the growing season.

Temperature

Petunias are tender perennials, but a lot of gardeners grow them as annuals. They love warmth and should be kept in temperatures between 65 and 85 F (18-30 C). They're not frost-tolerant, so if you keep yours outside be sure to bring it in when temperatures start to dip in the fall. Indoors, keep them away from cold drafts or heat vents, both of which can dry out the delicate blooms.

Pruning and Deadheading

Deadhead your Firefly petunia to encourage continuous blooming. New growth is the part of the plant that grows the brightest, so it's definitely in your interest to keep it producing.

If your plant becomes leggy, don't be afraid to trim it back – it'll respond with more new, highly luminescent growth.

Though traditionally used as annual bedding plants, petunias also are an attractive option for containers and hanging baskets. Their vibrant color, immense bloom, and general ease of care delight growers through the entire summer season. Like most plants, however, petunias need routine care to look their best. Consistent watering and attention to soil moisture is essential. But, do petunias need a lot of water?

How Much Water Do Petunias Need?

Petunia watering requirements depend upon several factors. While the plants are able to withstand brief periods without rain, supplemental irrigation is often needed to maintain the overall health of their foliage and the production of flower buds. Soil should remain consistently moist, drying only moderately between each watering. Growing conditions that are especially dry or warm often result in the need for an increased frequency in irrigation.

How Often Should I Water Petunias?

How often you water your petunias depends upon how they're growing.

How Often to Water Petunias in Pots

When it comes to watering petunias, those in pots and containers require water at a much greater frequency. Though weekly irrigation of potted petunias may be sufficient when the plants are small, more established containers will likely require water every few days. In warmer climates, daily watering may be needed to prevent the sudden wilt of plants.

How Often to Water Petunias in the Garden

Garden-grown petunias generally require irrigation with less frequency than those grown in containers. Still, the need for supplemental water will vary, depending upon both weather and the soil’s ability to hold moisture. Petunia plants benefit from weekly soaking, provided that their garden beds drain well and do not become waterlogged.

When to Water Petunias

Though plants can be watered at any time, experienced growers most often water them early in the morning or late in the evening. Watering before the day has warmed up will help ensure that petunia beds and containers are well hydrated and are able to withstand potential stressors related to weather. Though watering in the evening can help with uptake overnight, it’s best to allow for sufficient time for plant leaves and foliage to dry completely before sundown.

How to Water Petunias

Petunia plants are best watered deeply, so that the entire root zone is well saturated. To achieve this, irrigation should occur slowly. Drip or soaker hoses are ideal, as they are able to efficiently and effectively deliver water where it’s needed. Petunias can also be watered with cans or sprinklers, though gardeners should avoid wetting or splashing soil onto the plant’s leaves. Using proper watering techniques helps to prevent the development of disease and its spread.

Signs of Overwatered Petunias

Though petunias prefer soil to remain consistently moist throughout the season, overwatering the plants can be detrimental to their health. The sudden yellowing of petunia leaves is among the first signs that soils have become oversaturated. Soon, the petunia’s leaves will begin to wilt, and may even fall from the plant. Should the problem persist, issues with root and crown rot are likely, and can lead to the complete loss of plants.

Frequently Asked Questions

Do You Need To Fertilize Petunias?

Most garden experts agree that petunias are considered “heavy feeders.” Since these plants grow quite quickly, the availability of nutrients in the soil is paramount. This is especially true of varieties that are known for their productivity and stunning floral displays.

Learning more about when and how to properly fertilize petunia plants is essential to their growth, as well as their continued bloom throughout the summer. This applies to those planted in ornamental beds, as well as petunias in pots, containers, and hanging baskets.

How Often to Fertilize Petunias

Petunias grown in ornamental garden beds benefit from routine feeding, but they generally need much less than those in pots. Fertilizer for petunias in pots is especially important throughout their growing season, as nutrient levels quickly become depleted.

When to Fertilize Petunias

Petunia fertilizer is best used during periods of active growth. This includes amending the soil in preparation for planting, as well as regular feeding throughout the summer season. Though most manufacturer’s labels give growers specific directions as to the frequency of application, many non-commercial and organic products should be used based only on your soil’s composition and any soil deficiencies within your garden beds. Experienced growers often rely on soil tests to better meet the needs of their bedding plants.

How to Fertilize Petunias

Fertilizing plants properly depends greatly on the type of food being used. This is especially important with commercial fertilizers, which should be used only as directed. Granular fertilizers are most common and are worked directly into the soil at planting time. Granules or pellets can be used to side-dress plants, as well. This usually occurs later in the season, just before the production of flowers.

Water-soluble fertilizers refer to those that are diluted and used as foliar feed or soil drench. These types of feeds are generally used with greater frequency and are known for their ability to quickly deliver nutrients to plants.

Best Fertilizer for Petunias

Determining the best fertilizer for petunias varies and depends on several factors. At planting time, petunias can be placed into beds with soil that has been amended well. Experienced gardeners most often use a finished compost and a slow-release granular feed.

Petunia containers and pots should be filled with a high-quality potting mix. Foliar and water-soluble feeds can then be used throughout the summer to help maintain adequate nutrient levels for the continued production of flowers. Other types of fertilizer used with petunia plants include compost teas, blood meal, bone meal, and fish emulsion.

Frequently Asked Questions

In the horticulture world, finding a true, pure colored flower variety can be difficult. For example, a flower may have the word “white” in its name but instead of being pure white it may have tinges of other colors. When designing the perfect container garden or bed, your whole design may hinge upon that perfect true shade of white. Here at Gardening Know How, we understand how upsetting it can be when your “white” petunias look a lot more yellow or pink than white. Continue reading to learn more about true white petunias for the garden.

Growing White Petunia Plants

Petunias are one of the most popular garden annuals. They can be used in beds, borders, containers and hanging basket. They’re low maintenance, heat tolerant and most varieties bloom from spring to fall. Petunias also attract helpful pollinators, such as bees, butterflies and hummingbirds. In mild weather locations, petunias may even self-sow, providing an abundance of blooms year after year. Because of their vast color varieties, petunias are also excellent for seasonal/holiday displays, such as patriotic red, white and blue beds or pots. However, displays like these specifically require the blooms to be true to color.

Choosing White Petunias for the Garden

Naturally, the petunias you select will depend on the look you are going for and the other plants in the design. For example, if you are planting a border of white petunias in front of perennials such as coreopsis or black-eyed susan, you may find that petunias with yellow centers or veining look quite beautiful with these perennial flowers. Likewise, if you are planting window boxes which will hang from a dark colored house, you may find that only true pure white petunias stand out the way you want them to. With that said, below are some common white petunia varieties and their attributes: Easy Wave White – A true, pure white variety in the popular Wave Series, about 12 inches (30 cm.) tall and 42 inches (107 cm.) wide. Crazytunia Cherry Cheesecake – White flowers with pink to red petal margins reaching 12 inches (30 cm.) tall and wide. Success White – These white petunia flowers have yellow centers. Plants grow to 12 inches (30 cm.) tall and 32 inches (81 cm.) wide. Supertunia Pink Charm – Attractive white flowers with pink mid-veins that form a star. Sweetunia Mystery Plus – Lovely cream to white petunia blooms with purple to pink veining and centers. Capri White – Another white petunia with light yellow centers. The Capri Series is known as the most heat and cold tolerant petunia series. Opera Supreme White – Pure white petunias on this early blooming plant, reaches 10 inches (25 cm.) tall. Carpet Buttercream - Cream to white flowers with a light pink blush near petal tips. Damask White – Pure white blooms on a compact plant, 8 inches (20 cm.) tall and 12 inches (30 cm.) wide. Tritunia White – Pure white petunia flowers, 12 inches (30 cm.) tall and wide. Mambo White – Large pure white petunia blooms growing about 8 inches (20 cm.) tall and 24 inches (61 cm.) wide. Picnic White – Small pure white flowers reaching around 12 inches (30 cm.) tall and 24 inches (61 cm.) wide. Storm White – Pure white petunia flowers. 14” tall and 16” wide. Shock Wave Coconut – White flowers with chartreuse centers and mid-veins, 8 inches (20 cm.) tall and 24 inches (61 cm.) wide. Celebrity White – Pure white petunia reaching about 12 inches (30 cm.) tall and wide. Limbo GP White – Pure white flowers with ruffled edges, 10 inches (25 cm.) tall and wide.

Petunias are perfect bedding or container plants. If you are planning a hanging basket with a certain color scheme such as pink, you will want to know all the pink petunia varieties. There are several pink petunia flowers, some of which are in the "wave" category, while others sport double petals. A list of their attributes and names can help you decide which ones to select.

Choosing Pink Petunia Flowers

A mass of pink bubblegum flowers makes an outstanding and bright statement. Petunias that are pink provide several unique attributes that can enhance such a display. There are compact to mounding forms, tennis ball to dime sized blooms, plus many more variations such as striping and number of petals. If pink is your color, you're in luck, as most of the available varieties come in this sought after hue.

Wave and Carpet Varieties

The "Wave" type petunia has been around for several decades. These fabulous plants will spread out and cover a bed in glorious flowery color. The carpet variety is similar but has smaller blooms and is lower to the ground, making a tighter, tidier groundcover. These pink varieties of petunia will grow rapidly and develop into a sea of bright blooms:

• Easy Wave Pink Passion – Deeply colored with a touch of lavender and vigorous grower
• Supertunia Watermelon Charm – Spreads up to 24 inches (61 cm.) in bright fuchsia pink
• Carpet Pink Morn – Multiflora variety of soft cotton candy pink
• Carpet Pink – Heat and disease resistant with compact pink petunia flowers
• Carpet Rose Star – Vibrant pink flowers with white striped petals
• Tidal Wave Hot Pink – Intense color and huge blooms

Frilled and Double Petal Pink Petunia Varieties

If you want something unique, try ruffled, frilled, and multi-petal petunias that are pink. These selections offer more elegance and are transformed into something exceptional. New offerings have heat and rain tolerance to protect the delicate petals.

• Double Valentine – Mounding plant with masses of pink blooms
• Espresso Frappe Rose – Deep color and ruffled edges with some shade tolerance
• Double Cascade Pink Orchid Mist – A variety of pink tones from cotton candy to deep rose
• Double Cascade Pink – Extra large, dark rose colored frilled flowers
• Pink Fluffy Ruffles – Huge flowers up to 4.5 inches (11 cm.) across
• Frillytunia Pink – An old-fashioned form upgraded

Other Popular Pink Petunias

Selection of the most popular pink petunias and new introductions may also send you swooning for Valentine toned blooms. Barbie would be challenged to name her favorite.

• Aladdin Peach Morn – Early blooming and rain resistant
• Bella Star Rose and White – Rose blooms featuring a white star, weather resistant and compact
• Candy Picotee Rose – Small, 3 inch (8 cm.), hot pink flowers with white edges
• Dolcissima Fragolino – A mixture of raspberry to soft rose shades with deep stripes down center
• Aladdin Pink – Easy to grow and tolerant of many conditions
• Daddy Orchid – Soft color with a deeper toned center, compact with large blooms
• Dreams Neon Rose – Vibrant hot pink blooms with white throats

Petunias are extremely popular flowers, both in garden beds and hanging baskets. Available in all kinds of colors, sizes, and shapes, there is a petunia for virtually every situation. What if you know you want purple petunias? Perhaps you have a purple colored garden scheme. There are plenty of varieties to choose from. Keep reading to learn more about growing purple petunia flowers and choosing purple petunias for your garden.

Popular Petunias That are Purple

When you think of petunias, your mind might jump to classic pink. These flowers come in a wide range of colors, however. Here are some popular purple petunia varieties: “Sugar Daddy” – Bright purple flowers with a deep purple center that spreads out through the petals in veins. “Littletunia Indigo” – A compact plant that produces a prolific number of small, purple to blue blossoms. “Moonlight Bay” – Deep, rich purple flowers with creamy white petal borders. “Potunia Purple” – Extremely bright purple flowers that are vibrant all the way through. “Saguna Purple with White” – Large, bright magenta flowers that are edged with clean white borders. “Sweetunia Mystery Plus” – White to very light purple flowers with a deep purple center. “Night Sky” – Stunning deep purple/indigo flowers with irregular white speckles that earn this cultivar its name. “Purple Pirouette” – A thick double petunia with profuse, ruffled petals of white and dark purple.

More Purple Petunia Varieties

Here are some more popular and easy-to-grow petunias that are purple: “Espresso Frappe Ruby” – Frilled magenta flowers that grow so thickly it’s hard to see the leaves underneath. “Storm Deep Blue” – While the name says ‘blue,’ the flowers are actually a very deep shade of indigo/purple. “Mambo Purple” – Extremely large, 3.5 inch (9 cm.) wide flowers that are rich burgundy to magenta in color. “Merlin Blue Morn” – Don’t let the name fool you, these 2.5 inch (6 cm.) wide flowers deepen from light lavender to deep purple/blue.

Petunias are an old-fashioned annual staple that are now available in a plethora of colors. But what if you just want to see red? You’re in luck because there are many red petunia varieties available – so many, in fact, you may have difficulty choosing just which one to plant. Keep reading for some top choice petunias that are red.

Choosing Red Petunia Flowers

Petunias come in a myriad of not only colors, but shapes and sizes and habits – from clumping to trailing. The abundance and choice of red petunia varieties is just as varied. Many petunia flowers that are red are particularly fragrant as well as attractive to hummingbirds and pollinating insects. Before choosing red petunias, you will want to consider whether you wish to plant grandiflora or multiflora varieties, or a little of both. Here’s the run down: •Grandiflora petunias are the grandfather of petunias. They grow up to a foot (30 cm.) high and have large wavy blooms but are susceptible to damage from rain and heat. •Multiflora petunias are more compact and smaller than grandiflora, but they come in many shapes, sizes, and growth habits. They bloom more profusely and are more weather resilient. They also propagate easily.

Red Petunia Varieties

Below are some top picks when choosing and planting red petunia varieties for the garden. Aladdin Red is an early blooming, red ruffled, rain resistant grandiflora petunia that grows up to a foot (30 cm.) in height. Capri Rose, is as its name suggests, a rose red petunia with large blooms that flowers from spring through fall. This variety is very weather tolerant down to 25 F. (-4 C.) and up to 105 F. (41 C.)! They bloom earlier and finish off later than many other petunias. Capri Red is another frost hardy petunia with the same qualities as Capri Rose. If you love carnations, then Double Valentine is a gorgeous grandiflora with double red blooms on a mounding, upright plant that grows from 12-16 inches (30-41 cm.) tall. If you’re looking for red petunias to brighten up your containers, look no further than Mambo Red. These bright red petunias are weather tolerant multiflora petunias that bloom early with large flowers. They will not stretch, and blossom with blooms that are up to 3 ½ inches (8-9 cm.) across. Hurrah red petunias are among the earliest blooming multiflora petunias. They reach up to a foot (30.4 cm.) in height and flower consistently despite heat and humidity. Potunia Plus Red has large trumpet shaped blooms that attract hummingbirds. They require less water than other types of petunia which allows them to thrive in drought-like conditions. Supercascade Red is yet another variety of red petunia that produces large, showy blossoms on a bushy plant. Looking for spreading ‘Wave’ petunias? Try growing the Petunia Easy Wave Red hybrid. This trailing petunia looks lovely trailing over flower pots or filling in rockeries. This is just a sample of all the glorious red petunias to be had. Don’t overlook the ones that are predominantly red but include a splash of white or yellow. Both Candy Picotee and Frost Fire, for example, are red types surrounded by a ruffle of white, and Cha-Ching Cherry has a creamy yellow star in the center edged with red.

For decades, petunias have been a favorite annual for beds, borders, and baskets. Petunias are available in all colors and, with just a little deadheading, most varieties will continue to bloom from spring to fall. Each year new varieties of petunias are introduced, boasting improved colors and textures for the garden or containers. There are now even many true blue varieties of petunias available for any red, white, and blue patriotic container display you can dream up or simply for an addition to blue flower gardens. Let’s learn more about popular blue petunia cultivars to add to your garden.

Choosing Blue Petunias for the Garden

When choosing blue petunias, consider whether you absolutely need a true blue petunia variety or if a blue-purple type will suffice. In the horticulture world, color names and descriptions can be vague; blue is often used to describe plants with blue or purple blooms. Unfortunately, these days with so many easy programs for editing and altering pictures, the blue coloration of many plants available online is often enhanced to look bluer than it really is.

Common Blue Petunia Varieties

Below are some of the best blue petunia varieties and their descriptions so you will know exactly what colors or variations to expect:

• Damask Blue– Produces true navy blue blooms with yellow stamens. This compact variety stays low to the ground but is an excellent spiller for containers.
• Frost Blue– Produces deep blue blooms with white ruffled edges.
• Fuseables Pleasantly Blue– Produces light blue to lavender colored, ruffled blooms with dark blue veining.
• Mambo Blue– Produces dark blue-indigo blooms on a compact plant.
• Bella Picotee Blue– Produces deep blue, indigo to purple blooms with white edges and yellow centers.
• Surfina Bouquet Denim– Produces blue to violet colored blooms on a compact plant.
• Capri Blue– Produces large deep blue blooms with dark blue veining.
• Carpet Blue Lace– Produces light blue to lavender blooms with dark blue mottling and veining.
• Carpet Blue– Produces solid deep blue to purple blooms.
• Hurrah Lavender Tie Dye– Produces blooms that start out lavender but turn a sky blue as they mature.
• Daddy Blue– Large, ruffled, light blue to lavender blooms with dark blue veining.
• Storm Deep Blue-Produces large navy blue and dark purple mottled blooms.
• Night Sky– This variety would make Van Gogh proud, producing deep blue to purple blooms with irregular white spots that truly look like stars hanging in a dark night sky.

Petunias are extremely popular flowering plants that grow well in containers and as bedding plants in the garden. Available in very diverse varieties and colors, petunias can be found to meet just about any specifications you have. Whatever you want, you should have vibrant, beautiful blossoms all summer. However, this may not always be the case. What happens when your petunias start to wilt? Sometimes it’s easily fixed, but sometimes it’s a sign of something serious. Keep reading to learn more about petunia wilting problems and what causes petunias to wilt and die.

Troubleshooting Petunia Wilting Problems

Wilting petunia flowers can mean many things. Maybe the most common (and easily fixable) is improper watering. Like lots of plants, petunias respond to a lack of water by wilting. Don’t just water them more though! Wilting petunia flowers can also be a sign of too much water. Always check the soil around your petunias before watering–if the soil is still damp, don’t water it. Lack of sun can also lead to the wilting of petunias. Petunias prefer full sun and will produce the most flowers if they get it. They can survive in partial sun as long as they get five to six hours of direct light every day. If your petunias are in the shade, that might be your problem. Petunia wilting problems can also be a sign of insect or fungal issues:

• Aphids, budworms, and slugs like to eat petunias, opening up sores in the leaves that allow disease in. Lead slugs away from your garden with bait. Spray for aphids and budworms if you see them.
• Certain diseases like white mold, gray mold, black root rot, and verticillium wilt can all lead to wilting leaves. Avoid disease by watering your petunias early in the morning so water doesn’t sit on the leaves and planting your petunias far enough apart to allow for good air circulation. If your petunias contract a fungal disease, remove the affected parts of the plant and apply a fungicide.

There’s a lot to appreciate about petunias, cheerful annuals that bloom dependably from early summer until the first frost in autumn. These cheery garden favorites are available in an amazing range of colors, sizes, and forms. Read on to learn about a few of the different types of petunias.

Types of Petunia Plants

There are four main types of petunia plants: Grandiflora, Multiflora, Milliflora, and Spreading (Wave). All four are readily available in series, which are groups of plants with uniform size and flowering habits. The only varying characteristic is the range of colors of different petunia flowers within each series.

Varieties of Petunias

The oldest types are Grandiflora petunias, which were developed in the 1950s. Grandiflora petunia varieties boast blooms measuring up to 5 inches (12.5 cm.) across on bouquet-shaped plants. Although the flowers are spectacular, they tend to get tired and spindly in midsummer. Grandiflora petunias perform best in moderate summers without excess humidity or moisture. Grandiflora petunias series include:

• Ultra
• Dream
• Storm
• Daddy
• Supermagic
• Supercascade

Multiflora petunias are smaller plants with more numerous but smaller blooms. The stems are strong, which makes multiflora petunia varieties suitable for windy climates. The blooms tend to hold up a bit longer than Grandiflora petunia varieties, especially during rainy weather. Multiflora petunias are available in both single and double varieties. Popular Multiflora petunias include:

• Primetime
• Celebrity
• Carpet
• Horizon
• Mirage
• Primetime

Milliflora petunia varieties produce masses of 1- to 1 ½-inch (2.5-4 cm.) blooms on miniature plants. The mature size of the plants is generally about 8 inches (20.5 cm.) tall and wide. Milliflora petunias bloom early and are often grown in containers or hanging baskets. They are low-maintenance plants that require no deadheading. Milliflora petunias include Picobella and Fantasy. Spreading, or Wave petunias, are a recent addition with blooms typically measuring about 2 inches (5 cm.) across. The plants, which typically spread 2 to 4 feet (0.5 to 1 m.) by the end of the season, look great in containers and work well as ground covers. They tolerate heat and drought fairly well and generally require no deadheading. Wave petunias include:

• Easy Wave
• Shock Wave
• Avalanche

Petunias in full bloom are simply glorious! These showstoppers seem to come in every hue, tint, and shade imaginable. Search for “petunia” in the images section of your web browser and you’ll be treated to a cornucopia of color. But be careful. Viewing petunia photos might inspire you to run out to your local nursery and buy every petunia plant in sight. One of the fabulous features of petunias is that they blossom all season long. Whether you place them in a hanging basket or position them as a focal point in your annual flower beds, these prolific bloomers just keep producing. There is a caveat, however. Many gardeners find themselves back at the nursery complaining that “my petunias are getting leggy.” All the flowers end up at the end of the lanky bare stems. The look just isn’t very attractive. How disappointing. Don’t fret. You can learn how to stop leggy petunias.

How Do I Make My Petunias Fuller?

Preventing leggy petunias requires diligence and care. First, make sure you keep your petunias moist. If you have petunias in a smaller pot or basket, you may need to water them every day. Get into the habit of checking their moisture level each morning and give them a good drink of water. If your petunias are in the ground, then you may need to water them every three to five days. We all know that petunias bloom most prolifically if we deadhead the spent flowers regularly. But removing the petals isn’t enough. You also need to remove the seed if you want to learn how to stop leggy petunias. The seed pod looks like a little green (or tan if it is mature) chocolate chip nestled at the base of what looks like five skinny green leaves in a star-shaped pattern. Snip or pick off the flower below this section. Have you ever asked yourself, “How do I make my petunias fuller?” Preventing leggy petunias requires that you cut back the branches by one quarter or one half on a regular basis. This may be hard to do, as your petunia plant may be in full bloom when you do this. You can cut back all the branches at once. You will have a full, compact blooming petunia plant in a couple of weeks. You can also cut back (by 1/4 or 1/2) just some of the branches scattered evenly throughout the plant. Those branches will regenerate and rebloom, and then you can cut back the remaining branches two weeks later. Keep up this cycle throughout the season and you will be rewarded with a full look and an abundance of splendid petunia flowers.

No plant fills a container or bed with glorious colors faster than petunias, the workhorse flowers of the summer garden. But, as is the case in so many relationships, your admiration for your petunias may fade as the first flush of blossoms die and the plant begins to appear leggy and straggly. Even if you deadhead furiously, clipping off all those faded blossoms, the stems just keep growing longer. Do petunias need pruning? Yes, they do. Read on for more information about how to cut back petunias.

Do Petunias Need Pruning?

Many gardeners view annuals as disposable, and simply don’t know how to cut back petunias. But cutting back petunia plants is essential to keeping them looking their best during their short stay in your garden. You must have noticed how, over time, your fabulous hanging petunia baskets suddenly look awful, with stringy, long stems dangling limply down the side of the pot. The leaves are yellowing and the few colorful flowers hold onto the ends of the stems like sailors climbing out of the sea on ropes tossed their way. This is especially maddening when your neighbors on both sides have petunia baskets brimming with bright flowers all summer long. Pruning petunias makes the difference. Do petunias need pruning? They absolutely do, and the difference between gorgeous hanging baskets and stringy-looking ones involves appropriate trimming of these plants.

How to Cut Back Petunias

It’s easy enough to keep your petunias attractive all summer long if you begin early with maintenance and keep at it through the life of the plant. Maintenance is especially important if you brought home a full and flowering hanging basket in late spring. Before you begin cutting back petunia plants, take a close look at them. Notice that the plants – whether they are the Wave varieties, Super Petunias or just regular ones – only produce flowers at the very end of the stems. That means that as those stems grow longer, you’ll have flowers at the very end of bare stems. For best results, start pruning petunias soon after you install them in your yard. Cutting back petunia plants is not hard. You need to clip a few stems every week. Start early, even if this means you must trim off stems that have attractive flowers on them. Whenever your petunia stems are eight inches long (20 cm.) or longer, begin the pruning schedule. If your plants are small when you buy them and the stems are shorter than eight inches (20 cm.), you can wait awhile to clip. Here’s how to cut back petunias. Each week, you clip three or four stems in half, making the cuts above a node. The petunia plant will then produce two new growing tips just below each cut, and those tips will begin flowering soon. Pruning petunias regularly from the time you buy them will keep your plants gorgeous and healthy.

Petunias are fantastic annual bloomers. If you’re looking for bright colors, good variety, and forgiving growing conditions, look no further. If you’re really serious about adding some color to your garden or patio, however, you might want some companions for petunias to mix things up a bit. Keep reading to learn what to plant with petunias.

Petunia Companion Planting

One of the great things about petunias is that they are so diverse. Some varieties like “Wave” and “Surfinia” will trail out of a basket or creep along as a groundcover. Many grow straight up, but some get so top heavy when they do this that they’ll cascade over the edge of a pot. Companion planting with petunias is often about picking a plant whose shape accents its shape. If you’re planting in a container and want to try the Thriller, Filler, Spiller effect, plant small upright petunias around a tall, striking plant or add a trailing one to soften the container’s edge. Of course, color is another big concern with petunia companion planting. Petunias come in all kinds of colors-- make sure the flowers you pair yours with aren’t too similar in shade, or your look might be too uniform.

Choosing Companions for Petunias

There are more practical considerations when companion planting with petunias too. Petunias are very vigorous growers and bloomers, and they’ll muscle out any neighbors that are too delicate. They perform best in full sunlight and need at least partial light to grow. Pair them with other full sun plants for a really spectacular display. Similarly, companions for petunias should have relatively low water requirements. Petunias do need a decent amount of water, so don’t pair them with any cacti, but try to avoid plants that need continuously moist soil. Choosing plants that complement your petunias will provide season-long enjoyment.

Are petunias cold hardy? The easy answer is no, not really. Although petunias are classified as tender perennials, they are delicate, thin-leaved tropical plants that are usually grown as annuals due to their lack of hardiness. Read on to learn more about the cold tolerance of petunias.

Petunia Cold Tolerance

Petunias prefer nighttime temperatures between 57 and 65 degrees F. (14-16 C.) and daytime temps between 61 and 75 degrees F. (16-18 C.). However, petunias usually tolerate temperatures as low as 39 degrees F. (4 C.) with no problem, but they are definitely not plants that will survive the winter in most climates. Petunias are damaged extensively at 32 degrees F. (0 C.), and killed very quickly by a hard freeze.

Extending Petunia Cold Hardiness

You may be able to extend the life of petunias for a short time when temperatures begin to drop in autumn by protecting the plants. For example, cover petunias loosely with an old sheet in the evening, then remove the sheet as soon as the temperature moderates in the morning. If it’s windy, be sure to anchor the sheet with rocks or bricks. Don’t use plastic, which offers very little protection and can damage the plant when moisture collects inside the plastic. If your petunias are in pots, move them to a sheltered location when cold weather is predicted.

New Frost Tolerant Petunias

Petunia ‘Below Zero’ is a frost-hardy petunia that has been in development for several years. The grower claims that the petunia can tolerate temperatures down to 14 degrees F. (-10 C.). Reportedly, this bushy petunia will survive through winter frost and snow to bloom with pansies and primroses in early spring. However, this petunia may not yet be available at your local garden center. To err on the side of safety, it’s probably better to grow these flowers as annuals each year or you can try overwintering the plant indoors – even taking cuttings from plants to make new ones for next season.

Planting petunias in containers is a fantastic way to showcase them. Whether in hanging baskets or containers on tables or a front porch, growing petunias in pots brings vibrant color throughout the summer to whatever area you choose. Keep reading to learn how to grow petunias in containers.

Caring for Petunias in Pots

Petunia container care is very easy. Soil in containers is prone to heating up and drying out much faster than soil in the garden, but petunias are particularly hot and dry hardy. This doesn’t mean you should neglect your petunias, but you should allow the soil to dry out completely between waterings. Every few days, give them a long, slow drink. Wetting the flowers and foliage can promote disease, so water either from below or close to the surface of the soil. You don’t want to waterlog your roots either, though, so make sure your container has very good drainage. Petunias are heavy feeders. Apply a slow release fertilizer at the time of planting, then follow up with a liquid fertilizer every week or two throughout the season. Place your containers where they will receive full sun - six hours per day is good but eight is preferable for the fullest possible blooms.

How to Grow Petunias in Containers

You can purchase special trailing petunias, which will perform dramatically in containers. However, growing petunias in pots, regardless of their type, should not disappoint you, as long as you treat them right. When planting petunias in containers, be sure not to crowd your plants, limiting yourself to three per 12-inch (30 cm.) pot. If your petunias start to flag or grow leggy, cut them back and fertilize them. They should branch out with vigor. Cut flowers for bouquets frequently to encourage new growth and remove dead flower heads as soon as they appear.

If you’re not sure what to plant in your hanging baskets, you can’t go wrong with hanging petunia plants. With only a bit of effort on your part, petunias will reward you with masses of bright color all summer. Want to learn how to grow petunias in hanging baskets? Read on!

Planting Petunias in Hanging Baskets

Petunias are perfect for locations exposed to full sunlight. Look for cascading petunias, which include any variety that produces flowers on long, flowing stems. Planting petunias in hanging baskets is a cinch, as long as you use a sturdy container with at least one drainage hole. Fill the container with a lightweight commercial potting mix, which will promote healthy drainage. Never use garden soil, which quickly becomes compacted and too heavy for proper drainage. Mix a slow-release fertilizer into the potting soil at planting time.

Caring for Petunias in Hanging Baskets

Watering is critical when it comes to caring for petunias in hanging baskets. How often to water petunias in a hanging basket? This is a common question, and the answer is simple: water whenever the top couple of inches of soil feels dry to the touch. Hanging petunia plants may need water daily during the summer, and maybe even twice during periods of extreme heat. Water deeply, then let the pot drain. Never allow the soil to remain continually wet, as your petunias are likely to rot in soggy conditions. If possible, water the soil and not the foliage, as wetting the leaves can promote fungal disease. Feed petunias every week, using a water-soluble fertilizer formulated for flowering annuals. This, in addition to the slow-release fertilizer added at planting time, will ensure that the petunias have ample nutrients to sustain blooming all season. Remove wilted flowers as soon as they fade; otherwise, the plant will go to seed and stop blooming early. Cut petunias back by about half if they look tired and scraggly in midsummer. The rejuvenated plants will soon return with a burst of fresh blooms.

Petunias are beloved, no-fuss, annual plants that most gardeners can’t do without in the landscape. These plants are steady performers in summer, rewarding our neglect with bountiful flower displays and few pest and disease problems. Occasionally, however, a specific issue such as yellowing petunia leaves can be perplexing to gardeners.

Why a Petunia Has Yellow Leaves

In many cases, yellow leaves on petunia plants are cultural in nature but sometimes the cause is a common disease that can be spread from cucurbits. Some information on the exact symptoms and causes can help you determine if your petunia is destined for the rubbish bin or if you can save the plant to bloom another day. Petunias need well-drained soil, bright sunlight, and warm temperatures for best performance. These annuals come in a variety of petal formations, providing an ideal appearance for any type of flower display. When you see leaves on petunias turning yellow, it is important to note the pattern of fading. Some patterns indicate a destructive virus that can infect other plants in the garden, as it is transmitted through the feeding activities of aphids. How can you tell if a virus is causing yellowing petunia leaves or if you simply need to water or fertilize? The word “mosaic” is a clue.

Cultural Causes of Yellow Leaves on Petunia

Petunias need plenty of water but they don’t like their petals and leaves to remain wet. This can cause them to wilt and occasionally discolor. Water from the base of the plant deeply and allow the soil to dry out in the top few inches (5 to 10 cm.) before drenching the plant anew. Soil that doesn’t percolate leaves roots soggy and unhappy. Make sure your soil is a well-draining mix. Potting mixes should be half peat moss and half soil. The peat moss will provide adequate acidity to these plants. You should perform a soil test before installing in-ground plants to ensure adequate acidity. If the test comes back too alkaline, amend the soil to increase the acidity.

Nutrient Deficiencies Causing Petunias with Yellow Leaves

Young petunias need plenty of nitrogen to force green leaf and shoot development. When grown in nitrogen-poor soil, older leaves will turn greenish-yellow or even fully yellow. Chlorosis in the veins of leaves may indicate a potassium deficiency. When a petunia with yellow leaves has necrotic spots at the veins after fading, a higher dose of potassium is required. Magnesium deficiency creates a similar condition on the newest leaves. Young leaves on sulfur-deprived plants are decidedly greenish-yellow. Micronutrient deficiencies that can cause yellowing petunia leaves are boron, manganese, and iron. Iron is the most common deficiency in many regions. A soil test can help determine which nutrients need to be administered.

Leaves on Petunias Turning Yellow Due to Disease

The most probable cause of petunias with yellow leaves is the tobacco mosaic virus. Here is where the indicating word “mosaic” can help identify the disease. A mosaic is a collage of patterns that create an image. In the case of the yellowed petunias, the mosaic shows as mottling in golden yellow. It almost seems purposeful but instead is an indication that your plant has been infected with TMV. This virus affects cucumbers, tobacco, and other plants. It is transmitted through aphids but also in soil and through the hands of tobacco users. Once your petunias have the virus, there is no cure and they should be thrown out. Do not add them to the compost pile, as average temperatures are not high enough to destroy the disease and you could inadvertently spread it around your garden.

Gardeners with a bed full of inexpensive bedding petunias may not find it worthwhile to overwinter petunias, but if you are growing one of the fancy hybrids, they can cost more than $4 for a small pot. This means that you might not be able to use them as freely as you'd like. You can save money by bringing your petunia indoors over winter.

Care of Petunias During Winter

Cut the petunias back to about 2 inches (5 cm.) above the soil and plant them in pots before the first fall frost. Check them over carefully to make sure they aren't infested with insects. If you find insects, treat the plants before bringing them indoors.

Water the plants thoroughly and place them in a cool but above freezing location. Look for a spot in your garage or basement where they'll be out of the way. Check overwintering petunias every three to four weeks. If the soil has dried out, give them just enough water to moisten the soil. Otherwise, leave them undisturbed until spring when you can transplant them back outdoors.

Can You Overwinter a Petunia Plant as Cuttings?

Taking 2 to 3 inch (5-7.5 cm.) cuttings before the first fall frost is a great way to overwinter them. They root readily, even in a glass of plain water; however, the roots become a tangled mess if you put more than one cutting in a glass. If you are rooting several plants, you'll probably want to start them in small pots.

The cuttings root so easily that you won't have to cover them or start them in a greenhouse. Just remove the lower leaves from the cutting and insert them 1.5 to two inches (4 to 5 cm.) into the soil. Keep the soil moist and they will have roots in two or three weeks.

You'll know the cuttings have rooted when a gentle tug doesn't dislodge them. As soon as they root, move them to a sunny window. They won't need fertilizer over winter if you've planted them in a good commercial potting soil. Otherwise, feed them occasionally with liquid houseplant fertilizer and water them often enough to keep the soil lightly moist.

Caution About Patented Plants

Check the plant tag to make sure it isn't a patented plant before taking cuttings. Propagating patented plants by vegetative methods (such as cuttings and divisions) is illegal. It's fine to store the plant over winter or harvest and grow seeds; however, the seeds from fancy petunias don't resemble the parent plants. You'll get a petunia if you plant the seeds, but it will probably be a plain variety.

A summer blooming favorite, many gardeners use petunias to add color to beds, borders, and containers. Blooms are usually reliable until autumn, but what do you do if you have non-blooming petunias? Learning how to make petunias bloom is fairly simple. Read more to find out what may have caused the petunia plant with no flowers.

Reasons for Petunia Not Blooming

Here are the most common reasons for a petunia plant not blooming:

Poor lighting

When you find there are no blooms on petunias, the first thing is to check is the amount of light the non-blooming petunias are receiving. Check at various times of day to see if the petunia plants with no flowers are getting direct sunshine. Petunias need full sun for the most optimum show of blossoms. The plant may bloom when it is lightly shaded for part of the day, but as a rule, a petunia not blooming can be because it does not get at least six hours of direct sun per day. Move container planted petunias plants with no flowers into a sunny location. Ground planted, non-blooming petunias can get more sun by thinning or trimming surrounding plants that may be shading them. If you've planted petunias in a shady spot that can't be remedied, you may need to replant the petunia plant with no flowers.

Wrong fertilizer

If the lighting is correct and there are no blooms on petunias, perhaps they're not getting enough water or fertilization. Petunias are somewhat drought tolerant but will provide a more lush display when the soil is kept moist. Shake off excess water that is on the developing blooms of ground planted petunias; wet buds can rot away before blooming. If you haven't been feeding the petunia plant with no flowers, perhaps you should try this remedy. Many plants grown in nurseries are regularly fed with liquid fertilizer, but it only remains in the soil until it washes out from watering. It is possible that the petunias have been fertilized with a high nitrogen plant food, resulting in lush foliage, but non-blooming petunias. Change to a phosphorus heavy fertilizer, such as those labeled ‘bloom buster.' Bone meal is also a good source of phosphorus. Phosphorus is the middle number in the 3-digit fertilizer ratio listed on the packaging. Choose a product labeled 10/30/10. A balanced fertilizer may be effective toward summer's end if you're hoping for a final performance from your petunias.

How to Make Petunias Bloom Later

Deadheading spent blooms will encourage the production of more flowers. If foliage begins to brown and die as summer wanes, clip it off right above a set of healthy leaves. Pinch back the center of the stalks. Fertilize at this time with a balanced fertilizer, but one that has a high phosphorous number, such as 30/30/30. Enjoy the long lasting blooms of those petunias.

Petunias are so reliable and have such a wide variety of uses that it's no wonder it's one of the most popular garden flowers today. It's simple to buy a couple of petunia seedlings to fill one planter, but for mass plantings and garden edging, growing petunias from seed is the way to go. 

You'll save money because of the sheer number of plants you need, plus you'll have a much wider range of flowers to choose from. Garden centers only carry a few varieties already sprouted and growing, but you can find petunia flower seeds for different sized plants in almost every color of the rainbow.

Starting Petunia Seed Plants

The most important point to remember when learning how to start petunias from seeds is that these are summer, heat-loving plants. It does them no good to plant early in the garden, as they'll just sit and sulk or rot. In order to get these seedlings to planting size at the right time, you need to start them indoors at least ten weeks before planting time. 

In the north, this is around the first week of March and will be even earlier in more southern states. Although petunias are tough and resilient in the garden, they can be very delicate in the first weeks of life. Start out with a dedicated seed-starting soil mix and new or sterilized planting trays. 

Of course, you can also start them in eggshells for easier transplanting later. Sprinkle the tiny seeds on top of the mix and gently moisten them with a spray bottle. Cover the tray with plastic wrap to retain moisture and place it in a bright place out of direct sunlight that averages around 75 degrees F. (24 C.). 

Remove the plastic wrap once the seeds sprout and place the trays under lights in a cooler spot, around 65 degrees F. (18 C.) during the day. Keep the lights about 6 inches (15 cm.) above the tops of the plants. Use water-soluble fertilizer once every two weeks, and water the plants when the soil dries out.

Transplant the seedlings into individual pots once they develop two or three true leaves. Lift out individual plants with a wooden stick or butter knife, and transplant them into potting soil. 

Keep the soil moist but well-drained, and return them under the lights until it's time to plant them outside.

Additional Tips for Growing Petunias from Seed

When starting petunia seed plants, remember that the seeds are very tiny. It's easy to over-plant the trays, ending up with dozens of seedlings you don't need. Sprinkle them gently on top of the soil, using only a small pinch of seeds. Petunia seed propagation only happens when they get the right amount of light. Don't bother to buy special plant-growing light. Regular fluorescent lights work just as well. Place the plants on a shelf and hang the light directly above them. 

Move the lights upward as the plants grow, always keeping the lights 6 inches (15 cm.) above the leaves.

If you want to fill a flower bed or large planter with an eye-catching pop of color, wave petunias are the plant to get. This relatively new petunia variety has taken the gardening world by storm, and rightly so. Growing wave petunias is even simpler than caring for their earlier petunia cousins, which makes them ideal for busy gardeners and novice growers alike. Learn how to care for wave petunias and you may discover a new favorite flower.

Growing Wave Petunias

Wave petunia plants have a spreading growth habit, with the ability to fill flower beds with their blooms that sprout all along their stems, which can reach up to 4 feet (1 m.). Wave petunia plants are so versatile they can accent almost any part of your landscaping design. Create a dense hedge covered in blooms by planting a row of these plants along the base of a 3 foot (91 cm.) fence for support, or decorate a porch roof with giant globes of color by planting bright wave petunias around the base of a coir basket. Add wave petunias to large planters near your front door and allow them to cascade to the ground or plant a double row of them from the street to your porch to create a lined floral path.

How to Care for Wave Petunias

Caring for wave petunias is a simple task and won't take much time at all. These plants want to grow and thrive, and seem to increase on a daily basis. Plant them in full sun in moist, well-drained soil. Keep the soil moist, but never soggy. Feed them with an all-purpose fertilizer when you first plant them, and every two weeks after that until the middle of summer. Do you have to deadhead wave petunias? This is the sheer genius of these plants and what makes them so popular for use all over the garden. Unlike other petunia plants that need clipping and deadheading constantly throughout the growing season, waves never need deadheading. They will continue to grow and bloom without your having to snip one bloom.

Who doesn’t love petunias? They are endearing bedding flowers in bright colors and – with a little care – the blooms can last all summer long. I personally adore petunias and plant them in garden beds, hanging baskets, and containers too.

Like with all annuals, growing petunias adds gorgeous color to your garden for one season only. Their botanical job is to bloom, then set seeds that can produce flowers the following year.

Deadheading petunias after the blooms fade interrupts this process and, instead of growing seeds, the plants can bloom again, filling the garden with flowers all summer long.

Do You Need To Deadhead Petunias?

You don’t “need” to deadhead petunias. You won’t violate any laws by allowing the flowers to go to seed. But you’ll have to be okay with an increasing number of wilting blooms and empty stems in the middle of your flower bed.

But there are advantages to deadheading petunias. The top advantage is additional blossoms – in fact, if you deadhead your petunias regularly, you can have new flowers blooming all summer long. In addition, your petunias in hanging baskets or in garden beds will look lush and lovely as the new flowers come in.

Note that there are some types of petunias that are improved varieties, bred to continuously bloom. These varieties do not set seeds, so deadheading these varieties is not necessary. They will bloom and rebloom all season long which explains why they cost a bit more than seeded petunias (and may be worth it!)

When to Deadhead Petunias

You can grow petunias by planting seeds or by buying flats of flowers in the garden store. I must admit that I buy six-packs of starts because they begin blooming so quickly and light up the garden. They are quite cheap and every one of the starts thrives when transplanted.

But when I am planning on installing a lot of petunias, I’ll go with seeds. While plant starts won’t break the bank, seeds are even cheaper. They do take longer to bloom, since they have to germinate, produce stems and develop root systems before they flower.

But whether you buy plant starts or start your plants from seeds, they will eventually bloom. After they bloom, they will fade. Clearly, you don’t want to deadhead petunias until the flowers fade. The very purpose of deadheading petunias is to get rid of fading blossoms. So, the time to deadhead a petunia is when the flowers begin to wilt.

There is no specific day and time that the plants will bloom or fade. There are thousands of varieties of petunias, and they can start flowering at different times. The region, the climate and even the weather can impact the date that the plants start blooming. For deadheading petunias and pruning just about everything else in the garden, our gardening editors love the Felco F2 Classic Manual Hand Pruners, available from Amazon.

How to Deadhead Petunias

If only all garden tasks were as easy as deadheading petunias! How do you deadhead petunias? It’s a simple procedure. When you see a wilted flower, you simply remove the bloom, taking out the ovary - a small bud structure just behind the flower. That is where the plant produces seeds, so removing it is the act that stops seed production. You can clip the faded flower off with scissors, a pruner, or just using your fingers.

If you are wondering how to deadhead petunias in hanging baskets, you do it in the same manner. You clip off each faded bloom and the ovary beneath it.

Frequently Asked Questions

Most flower gardeners are familiar with growing petunias from seed. They're sturdy, reliable flowers for borders, planters, and hanging gardens. What about taking petunia cuttings? Learn how to start petunias from cuttings to create dozens of new plants that are clones of the original and that will guarantee blooms earlier than any of your neighbors.

Why Propagate Petunia Cuttings?

If you want to propagate petunia to grow the same type next year, there are a couple of problems with simply saving the seeds and planting them next year. First, if you live in the northern half of the country, it may be the middle of summer before you see any blooms on your petunia plants. Second, if the petunias you grow and care for are hybrid varieties, the seeds you collect won't breed true the next year. The way to grow more plants for next year's garden is by rooting petunia cuttings.

How to Root Petunia Plants

How to root petunia plants? The best way is to begin with the absolute best example of the plant you have in your garden. You'll be making exact clones of these plants, so choose the ones with compact growth and bright, big flowers in colors you love. Take cuttings from the plant in the fall before frost arrives. Rooting petunia flowers is very simple as long as you prepare correctly. Make a mix of equal parts peat moss, sand, and plant food. Fill a flat with the mixture and mist it to moisten it all the way through. Clip leaves from the tops of the petunia plants, making sure you collect soft, flexible examples instead of older, woody types. Wrap the leaves in a damp paper towel until you can bring them inside to plant. Dip the end of each leaf into rooting hormone powder. Make a hole in the soil mix with a pencil and place the powdered stem in the hole. Push the soil around the stem to hold it in place. Plant all the leaves in the same manner, keeping about 2 inches (5 cm.) between each one. Place the tray in a cool, dark place for about three weeks. After this time, gently pull on one leaf to see if roots have begun to grow on the stem underground. Once all the leaves have stems, transplant them into individual small pots. Transfer the pots to shelves with grow lights and grow them throughout the winter. You'll have bloom-ready petunias as soon as the frost leaves, first thing next spring.

Whether spilling out of baskets and boxes or filling the fronts of beds with their bright flowers, petunias make every space a little more merry. These tough flowers tolerate a lot of abuse and neglect, though pests and diseases can create problems with growing petunias. Read carefully through the list of common petunia flower issues to learn how to treat petunias ailing from a variety of causes.

Pests of Petunias

There are a number of pests of petunias that can affect these plants. Here are the most common: Mites: Mites are nearly microscopic pests that suck the juices directly out of petunia cells. These cousins to the spider may cause leaves to curl, cup, or flowers to discolor and stiffen. Spider mites also leave thin webs behind where they feed. Spray your petunias with neem oil once a week until all signs of mites are gone. Caterpillars: Caterpillars chew through foliage and buds, sometimes causing extensive damage in no time. They're easy to see if you pick through thick foliage. The best solution is to remove them by hand and drown them in a bucket of water daily, but if you can't bring yourself to do it, sprays of Bacillus thuringiensis applied weekly should knock them out quickly. Thrips: Thrips can carry viruses to petunias and may cause leaves to turn papery or flowers to develop white spots, known as “color break.” They can be difficult to see, but look like very tiny, fat ants when running around on your plants. Neem oil or insecticidal soap will knock them out in a few thorough weekly sprays.

Petunia Diseases

Below are common diseases affecting petunia plants: Root, Stem, and Crown Rots: Root, stem, and crown rots commonly affect petunias planted in areas of poor drainage or that are chronically overwatered. Leaves wilt despite regular watering and stems may begin to soften. Correcting the drainage and watering less frequently is the only solution if an affected petunia can be saved at all. Often, it's easier to pull plants and start over early in the season. Botrytis Blight: Botrytis blight may cause spots or other discoloration on flowers and leaves that eventually sprout brown-grey spores. Again, this disease is favored by wet bedding conditions, so let up on the watering when it appears. Prune out any diseased sections of your plants and pick up fallen debris; drying out the bed should prevent re-infestation. Powdery Mildew: Powdery mildew doesn't need soaking wet conditions to thrive, but often appears where plants are spaced too tightly, obstructing airflow. Look for white, powdery spots of spores that spread or cover leaves and flowers completely. Powdery mildew can be treated with neem oil, but you should also correct the conditions allowing this disease to get a foothold. Verticillium Wilt: Verticillium wilt causes an overall decline in plant vigor, often causing older leaves to wilt before younger ones, or only part of a plant to die at first. There is no cure for verticillium wilt, so pull your plants and try again in pots. In some areas, the soil can be heated enough through soil solarization to kill the fungal pathogen. Viruses: Several viruses affect petunias, causing leaves to develop yellow spots, mosaics, halos, or bullseyes. Unfortunately, petunia viruses cannot be cured. If you suspect virus in your plants, use extra caution when pruning or working with the plants to slow the spread of disease. Many plant viruses are vectored by small insects, check your plants carefully and treat any you find if you hope to save the non-symptomatic plants in your beds.

How To Grow And Care For Petunias In The Garden

Showy petunias are among the most popular flowering annuals. They are prized for their pretty blooms that come in a variety of colors, sizes, and growth habits. Learning how to care for petunias is straightforward, but they require some special care to keep them looking their best.

Quick Facts

• Botanical name: Petunia x hybrida
• Height: 9 to 12 inches (23 to 30 cm)
• Spread: 1 to 3 feet (.30 to .90 m)
• Sun exposure: Full sun
• Soil requirements: Average, well-drained
• Hardiness zones: 10 to 11
• When to plant: Spring

Petunia Care

Caring for petunias is relatively simple if you provide them with the right growing conditions. A little pruning, full sun, and moist, well-drained soil should keep them happy and blooming all summer and into the fall.

Light

A petunia will do best in full sun but will tolerate partial shade. Too much shade results in unattractive leggy growth.

Water

Petunias prefer medium moisture in the soil. They will tolerate some neglect when it comes to watering. Once a week is ideal, but spreading types of petunias need more water.

Temperature & Humidity

Petunias tolerate heat and don’t require a lot of humidity. They will not survive low temperatures but will thrive between the last frost of spring and the first of fall.

Soil

Petunias need soil that drains well, so amend as needed to avoid soggy soil or standing water. In terms of fertility, petunias tolerate average to poor soil. For the best results, add organic matter to poor soil.

Fertilizer

Use a balanced fertilizer at the time of planting petunias, then use a fertilizer designed for promoting flowers every couple of weeks during the growing season. Spreading types of petunias are heavier feeders. Fertilize these once a week.

Problems, Pests & Diseases

There are not many serious pests or diseases associated with the petunia flower. Aphids, slugs, and snails may cause some damage. Root rot or mold can occur in wet conditions and with poor drainage.

How to Grow Petunias from Seed

The easiest way to grow petunias is to buy transplants in the spring from your local garden center. However, for hard-to-find varieties, you might want to start with seeds. Petunias need several weeks from seed before being ready to transplant. Plan for about 10 to 12 weeks indoors before the last frost.

Sow the small seeds directly on the top of moist soil or seed starting mix. Keep them moist but not soggy, and leave them in a warm, sunny place. Harden transplants by placing them outside in a sunny spot during the day for a few days, bringing them back in at night.

How to Deadhead Petunias

Petunia varieties with larger flowers must be deadheaded to get new blooms. Simply pick off and dispose of spent flowers as they appear.

Propagation

The best way to propagate petunias is by cuttings. Most varieties are hybrids, which means the seeds won’t breed true. Clip off a healthy stem and remove the lower leaves. Place the cut end of the stem into moist potting mix. You dip it in a rooting hormone first for better results. Keep the cuttings moist and in a cool, dark spot as they root.

How to Grow Petunias in Pots

Petunias do very well in containers. Some varieties trail and spill over the edges of pots. You can plant petunias alone or mix them in with complementary container plants. Use a quality potting mix, and be sure the container drains well. You will need to water potted petunias more frequently and ensure they get plenty of time in the sun. Because they are annuals, you will not need to repot petunias.

Overwintering

Most gardeners treat petunias as annuals, but they are actually very tender perennials. If you have a special variety, you might want to overwinter it for next year.

Cut the plants back by about a third. Bring containers indoors before the first frost. Dig up bed plants and transfer them to containers. Provide the plant plenty of sun and water to start and then begin to reduce them over several weeks. This allows the petunia to go dormant. As it loses its leaves, move the plant to a cool, dark location for the rest of the winter.

Petunia Varieties

There are hundreds of varieties of petunia hybrids. They generally fall into four categories:

Grandiflora. These are large, single or double flowers in a variety of colors. Grandiflora petunias tolerate heat less well than other types.

Multiflora. Multiflora petunias are more compact with smaller flowers, but they bloom heavily all summer. They tolerate wetter conditions.

Milliflora. These petunias have many small blooms. They look very nice in containers.

Spreading. Also known as groundcover petunias, spreading types growl low and wide. They make good flowering groundcovers and look nice in hanging baskets.

Frequently Asked Questions

Are Petunias Perennials?

Petunias are very tender perennials and are hardy only in zones 10 and 11.

Do Deer Eat Petunias?

Yes, deer do eat petunias. As long as they don’t eat all of a plant, it will regrow.