The 7 Fast-Growing Flowers I’m Planting In August For Gorgeous Fall Color
I used to think the garden was winding down by late summer – but these blooms have well and truly proved me wrong.
Fun fact about me: I am always on the hunt for fast-growing flowers that can add some serious color to my garden before the fall rolls around. Especially at this time of year.
Why? Well, because every single time August rolls around, I start noticing the gaps. The spring annuals have lost their sparkle, all but the longest-blooming perennials are beginning to fade, and suddenly the garden feels like it's quietly winding down long before I'm ready to say goodbye to summer.
For too many years, I assumed I'd missed my chance. Once August arrived, I thought it was too late to plant anything new and I'd simply have to wait until next spring. Thankfully, that's one of those gardening myths that's wonderfully easy to prove wrong, as August can be one of the smartest times to add fast-growing flowers to the mix.
7 Fast-Growing Flowers You Can Still Plant In August
If you want to plant fast-growing flowers this month so that you have oodles of color over the autumn, you're in luck! Warm summer soil helps roots establish quickly, which means many annuals race into bloom before the first frost; in fact, gardeners in warmer USDA zones can often enjoy flowers well into October or even November.
There is a knack to it, of course, and it's this: choose the plants that don't mind getting a late start. The ones that grow astonishingly quickly from seed (or even the ones best planted as young nursery plants for an almost instant splash of color).
Before you fill your cart, though, it's worth checking your USDA hardiness zone and average first frost date. Gardeners in Zones 8–10 have a much longer planting window than those in Zones 3–5, but every region still has options for extending the season.
With that in mind, then...
1. Calendula
If I could only sow one fast-growing flower in August, calendula would be near the top of my list (especially so now that scientists have been raving about its unexpected superpowers of late).
Calendula marigolds make pretty border plants and they are safe to eat. We love this yellow variety!
Its cheerful orange and yellow blooms often appear in as little as six to eight weeks, making it perfect for late-season color. Better still, calendula actually prefers the cooler weather that arrives as summer fades, so it often performs better in fall than it does during the hottest weeks of July.
Winner winner, chicken dinner!
2. Sweet Alyssum
Want fast-growing flowers that spell big, bold, beautiful color for fall? Never underestimate this little plant.
Sweet alyssum quickly forms soft cushions covered in tiny, honey-scented flowers that pollinators absolutely adore. Garden centers often stock young plants throughout late summer, making it one of the easiest ways to refresh containers and borders.
In warmer parts of the country, it can continue blooming right up until winter. Bag yourself some Sweet Alyssum Flower Seeds from Walmart, then, and get sowing.
3. Nasturtiums
Nasturtiums are one of those fast-growing flowers that seem to grow with astonishing enthusiasm, with their rounded leaves and jewel-colored blooms quickly scrambling through containers, raised beds, and vegetable gardens.
Both the leaves and flowers are edible, which is no small boon in this day and age. And, from seed, many varieties bloom within six to eight weeks. Give the Sweethearts Mix Nasturtium Seeds from Burpee a go.
4. Violas
Most people think of violas as spring flowers, but I actually love planting these fast-growing flowers toward the end of summer.
As temperatures begin cooling, they burst into flower and often continue long after many summer annuals have given up. In milder climates, they may even flower through winter. That being said, though, I suggest you plant nursery-grown starts in August for the quickest display; something like the Halo Golden Yellow Hardy Violet Perennial from Walmart should do the trick.
5. Zinnias
If your first frost is still several weeks away, zinnias are absolutely worth squeezing in.
These cheerful annuals love warm soil, which means August-planted nursery starts settle in quickly and can keep flowering until frost. In warmer USDA zones, you can also sow fast-maturing dwarf varieties directly from seed, though gardeners in cooler regions will usually get the best results by starting with established plants.
One of my favorite things about zinnias is that the more you cut them for bouquets, the more flowers they seem to produce. They're also magnets for butterflies, making them one of the easiest ways to add both color and pollinator activity to a late-summer garden.
Pick yourself up a pot of zinnias from Walmart, then, and get cracking!
6. Lantana
If your summer garden is looking tired, lantana is one of the fastest ways to bring it back to life.
This heat-loving flower seems to become happier as temperatures climb, producing clusters of tiny blooms in fiery shades of orange, pink, yellow, purple and white. While other plants start struggling in late summer heat, lantana keeps flowering – often right through the first frost.
It's especially valuable for gardeners in warmer USDA zones, where it can grow as a perennial and continue returning year after year. In colder regions, treat it as a colorful annual and enjoy its long final burst of flowers. A Lantana Rose Live Starter Plant from Walmart should do the trick nicely.
7. Marigolds
If there's one flower that refuses to admit summer is ending, it's the not-so-humble marigold.
Garden centers are usually still well stocked with marigolds in August, making them an easy way to refresh tired containers, borders, or vegetable gardens. Once planted, they'll happily keep pumping out cheerful yellow, orange, and deep red blooms until the first hard frost with very little fuss.
I also love that marigolds earn their keep. They're excellent companion plants in edible gardens, attracting pollinators while adding bold color exactly when many summer flowers are beginning to slow down.
Shop Marigolds:
Three pots of marigolds, all beautifully yellow and ready to go? Sounds a deal to us!
Orange marigolds are just so synonymous with late summer and fall, aren't they?
This looks like a stunning fall bouquet just waiting to happen, doesn't it?
Now, it's important to remember that the beauty of late-summer planting is that there isn't one perfect flower for every garden. Your USDA zone, first frost date and growing conditions all make a difference.
If you're gardening somewhere with a long, hot growing season, don't overlook heat-loving favorites like angelonia, pentas, celosia and salvia. These flowers can handle the toughest weeks of summer and continue bringing color when many other plants start to fade.
In cooler climates, the smartest approach is often choosing fast-growing annuals or picking up established nursery plants rather than starting everything from seed. Marigolds, petunias, snapdragons and violas can all give you that fresh burst of color without needing months to establish.
Not to get all Ryan Gosling in The Notebook about it, but it wasn't over. And honestly? Neither is the gardening season.
