6 Longest-Flowering Annuals for Hanging Baskets & Window Boxes – Plant Now for Dazzling Blooms That Last Until the First Frost
Most plants fade by midsummer, but these annuals are the exception. Plant them now for hanging baskets and window boxes full of blooms until the first frost.
Many of us plant hanging baskets and window boxes that stop performing by mid-July. We think there’s nothing to do but keep watering our containers that are past their prime. But with a little planning and thought about plant selection now before you pot up your containers, you can avoid this common pitfall.
The annuals worth building a basket around aren’t always the most dramatic at the garden center in spring and early summer. But they’re the ones that still look reasonable in late August when everything else has given up.
For the best display of summer flowers in containers, you have to choose varieties that continue to perform from June until the first frost. These don’t need constant intervention to shine. They have long bloom seasons that ensure hanging baskets and window boxes dazzle from the beginning of summer to the start of fall.
Longest-Blooming Annuals for Containers
These are all plants that earn their place in a hanging basket or window box because of their ability to bloom from the beginning to the end of summer.
1. Calibrachoa
Calibrachoa (Calibrachoa spp.) might be the most reliable long-season annual in this category. The flowers are petunia-like and come in a wide variety of colors, but the real selling point is how this plant handles summer on its own. It's self-cleaning, so spent blooms drop without deadheading and new ones follow continuously.
Calibrachoa is equally effective spilling over the edge of a window box or out of a hanging basket. However, it is worth noting that this plant is iron-hungry and prone to chlorosis at high pH.
Most varieties of calibrachoa bloom from late spring through hard frost without many dips in between. Feeding makes a real difference in flowering, though. Calibrachoa is a hungry plant, so a slow-release fertilizer from Amazon worked in at planting followed by weekly liquid feeding through the season keeps the flowering well into autumn.
Shop tons of calibrachoa in a gorgeous assortment of colors from Home Depot.
2. Trailing Petunia
Modern types of trailing petunias (Petunia × atkinsiana) have been bred for better spread and summer endurance. So most newer petunias hold up well through July and August in a way older bedding varieties rarely manage.
Petunias keep flowering without deadheading. Spent blooms drop and new ones follow without any work from you. Their fragrance is a real bonus, too, especially near a door or seating area. The sweet scent carries well on a warm evening.
Fertilize petunias weekly and keep them watered well. These classic annual flowers are thirsty, but they can flower right up until frost in return with the proper care.
Try this elegant trailing Supertunia from Proven Winners for a stunning basket display.
3. Bacopa
Bacopa (Sutera cordata) is technically a filler plant, but it does more work than that suggests. The growth trails gently – rather than sprawling – and the tiny white or pale pink flowers are densely packed so the whole plant looks frosted for most of the summer. This is useful when larger flowers become patchy in July.
Spent flowers drop without any help, so bacopa stays beautiful without regular deadheading. Consistent moisture is key and so is afternoon shade, rather than full afternoon sun. This plant is not demanding, but it does best when you give it plenty of water and a little shade during the hottest hours of the day.
You can find bacopa plants online from Home Depot.
4. Verbena
Verbena (Verbena spp.) brings heat tolerance that most other basket plants can't match. In a hanging basket on a south-facing wall where containers bake all afternoon, verbena tends to be the one plant still performing in August when everything else has faded.
The flower clusters are dense and bright, ranging from white to purple and coral. Trailing types of verbena that are bred for containers have better spread and coverage than older garden varieties.
Water-storing cyrstals from Miracle-Gro mixed into the compost at planting extend the interval between waterings noticeably, which is useful for any sun-facing basket. Trim occasionally if your verbena gets leggy, otherwise feed and water it regularly and verbena largely takes care of itself.
Explore lovely varieties of verbena for sale at the Home Depot.
5. Trailing Lobelia
Trailing lobelia (Lobelia erinus) looks best during the cooler parts of the season, which tells you something about where it fits in a basket. In hot climates or during heat waves, it flags – color fades and growth stalls – and doesn't really come back until temperatures cool off.
Pair lobelia with plants that hold onto colorful blooms through the hottest weeks and it will return with a second flush of flowers after temperatures fall a bit. North-facing and partially shaded locations help sort out this problem.
Get live trailing lobelia plants for your hanging baskets from Walmart.
6. Ivy-Leaf Geranium
Ivy-leaf geraniums (Pelargonium peltatum) are the most drought-tolerant option on this list. In a hanging basket or window box that matters more than in-ground plants. Containers dry out fast, especially in warm weather, and this pelargonium's forgiveness when you miss a watering is one of its biggest benefits.
A coco coir basket liner from Amazon retains moisture well, making it a good option for wire baskets that bake in the afternoon sun.
The trailing growth of this type of geranium is vigorous and the flower clusters are dense from late spring right through autumn, with very little care needed from you. During a really warm summer, these plants can put on a serious show.
