Does your late-summer garden remind you of a mangy dog? We get pretty enthusiastic about choosing plants we think are pretty without really thinking of how long they'll produce colorful flowers and rich, lush foliage.
The best garden designs use plants with complementary maturity rates. Some late-blooming annuals and perennials do well planted after the peak of summer, growing quickly for a fall display. Others spend the first part of the season getting established, waiting until the conditions are just right.
When spring and early summer plants are past their prime, these beauties are ready to rule the garden. You know. Kinda like how Millennials are on the rise, to the chagrin of dusty ol' Boomers. (Oops! Don't worry. We're not going to play into the war between the generations. Much.)
Plant diversity is essential to our ecosystems, and diverse development rates are just as important. Varied bloom periods directly correlate to the life cycle of the organisms in our environment. Plants, insects, birds, mammals, reptiles, and amphibians depend upon one another for food and reproduction, and each helps shape the evolution of the others.
Ecology aside, nobody wants their garden to burn out in the middle of summer. Long-blooming and fall-flowering plants (both annuals and perennials) help hide fading foliage, and subtly transition a garden from one color theme to another. It's all about the varieties you choose, and how you use them.
What to Consider When Choosing Late Blooming Plants
- Look for species whose blooms and foliage regenerate after cutting back.
- Many annuals stay vibrant longer when they're sheltered from the afternoon sun.
- Experiment with plants noted to prefer "full sun to partial shade." If you're in a particularly hot area, they might tolerate more shade than you'd expect.
- Be careful not to plant late-season species that will block sunlight and airflow to nearby perennials.
- Plants that grow faster than their neighbors, but don't reach the same height and bulk, might shade out slower-growing plants.
Late Season and Long-Blooming Annuals
Annuals grow from seed and completely die off in a single season. In spite of their short life cycle, they mature quickly. Most bloom profusely, and many will keep producing flowers with minimal primping. Annuals with the quickest maturity rates are excellent candidates for staggered (or successive) planting. Here are some of our favorite long-blooming and late-season annuals:
- Alyssum (annual and perennial varieties): April through the first frost, with a bloom break at peak summer temperatures.
- Aster: July through September.
- Candytuft: June through the first hard frost.
- Coleus: Treated as an annual below zone 9. Known and grown for its colorful, showy foliage.
- Cosmos: June through September.
- Dahlia: June through September (depending on species). Note, you can dig up dahlia tubers for replanting the following spring.
- Flowering kale: Late summer into winter; frost triggers pink and purple coloration. Non-tasty ornamental variety.
- Marigold: Late June until the first frost.
- Pansy: Perennial usually grown as annual. All season long in temperate or cool climates; will tolerate light frost in fall.
- Portulaca: June until frost.
- Scarlet runner bean: July through October; a frequent harvest of the bean pods encourages prolonged bloom.
- Sunflower "Lemon Queen": This and other Helianthus annuus sunflower varieties bloom from mid-summer up until the first frost.
- Scarlet sage/salvia: Grown as an annual below zone 9. Blooms mid-spring through fall.
- Wax begonia: Treated an annual below zone 9. Blooms May until the first frost.
- Zinnia: June until the first fall frost.
Late Season Perennials
Perennials establish themselves in their first season, and while they'll usually flower that year, most species don't peak until their second or third. But when they do, they're amazing. Use late-blooming perennials as "anchor points" in your garden, around which you can infill with annuals.
- Anise Hyssop: June through September.
- Bee Balm (Monarda): June through September.
- Butterfly Bush: Spring until the first frost.
- Cinquefoil: June until September, possibly until the first frost.
- Clematis "Sweet Autumn": Late July through September.
- Coneflower (Echinacea): July until the first frost.
- Helenium autumnale (Sneezeweed): August until first hard frost.
- Heliopsis: June through August.
- Japanese Anemone: Mid-summer until late fall.
- Lavender (Lavandula x inermedia, Lavandula stoechas): The former blooms mid-summer into fall; the latter blooms spring to fall.
- Mexican sage: August until the first hard frost.
- Moss Verbena: May until frost.
- Russian sage: July until October.
- Sedum "Autumn Joy": July until the first frost.
- Coreopsis: Spring until the first frost.
Don't Forget Cool-Season Produce
Leafy greens bolt when it gets too hot, but you can try succession planting throughout the season provided they have shade in the hottest part of the day. Mulch deeply, irrigate at ground level and put salad and sauteed greens on the menu every chance you get.
The sting of frost brings out the sweetness in many veggies, including carrots, kohlrabi, beets, cauliflower, bok choy, and broccoli. Refer to your average fall frost date and use the maturity date listed on your seed packet to decide when you should plant a second round of vegetables.
Tips and Tricks for Extending the Bloom
Don't feel bad. We all abuse our gardens in the middle of summer. We go on vacations, stray from our regular schedules. Sometimes, it's just too damn hot to do garden chores or drag a hose around the yard. Make your job as easy as possible by choosing plants with care requirements within your wheelhouse, and by taking care of these easy tasks. And if we haven't said it enough...consider installing drip irrigation. You can still hose down your creepy neighbor anytime you want. But healthy plants that get consistent water and the minimum of care will produce the best flowers after the heat subsides.
Develop a gardening planning scheme
Plants don't give a rat's backside about almanacs, and your specific microclimate might prolong or shorten a plant's predicted maturity rate. Usually not by much—but gardeners who really like to nitpick might try keeping a record of planting dates, temperatures, and data on flowering periods. You can get as detailed as you want, and either keep a notebook (which, by the way, will get dirty) or try out a well-reviewed gardening app like GrowVeg.
Map out all your gardens with one of the handy online programs we found on The Spruce. Be warned: You'll end up spending more time messing around with theoretical designs than you'd expected. Some of these interactive programs could draw a huge market share away from Candy Crush. (Do people still play that?)
Deadhead spent flowers
When a flower's petals fade, the plant channels all its energy into producing seeds. If you lop off the flowers, the plant will redirect its efforts back into creating new blooms. Plants are determined to reproduce, and that's why deadheading prolongs the bloom. Snip as you go for best results, and be sure to clean your shears or knife in between plants to reduce the risk of spreading disease.
Shear back annuals in mid-season
Annuals that tend to lose their oomph as the summer heats up might make a comeback on the other side of the temperature spike. Dixie Sandborn from Michigan State University Extension wrote:
Petunias, marigolds, impatiens, zinnias and salvia will all give you a great show after a shearing or 'haircut' in midsummer. It takes about two weeks for a good show of color, but is well worth it.
So there you have it! Shear them back by half, treat them to an all-purpose fertilizer, and irrigate regularly.
Insulate the soil with mulch
Mulch will protect the plant's roots from heat, reduce moisture loss, and inhibit weed growth. Use at least three inches—more if you can get away with it. Be sure to leave a gap around plant stems to prevent rot. Want to learn more about mulching? Of course, you do! Check out our recent guide to the different uses and types of garden mulch.
Maintain your perennials for optimal blooms
Plan for next season's late-summer floral displays! If you need to divide your perennials, do so just after they've finished flowering. Dividing your perennials after their second or third year keeps them healthy and encourages more vibrant blooms. Put divided plants into soil amended with lots of rich compost. Perennials also appreciate a high-phosphorus fertilizer before you put them to bed for winter.
Fall Flowers Help Beneficial Bugs Stock Up for Winter
Summer and fall-blooming plants give bees, beetles, hoverflies, and other garden helpers the boost they need to survive the winter. The longer your garden's open for business, the better.
Plants that bloom during or just after the peak of summer break—the "dearth"— bloom during a period when high heat dries up nectar on early-flowering plants.
Honeybees spend a lot of time in late summer fanning their hives to regulate temperatures. In doing so, they're also reducing the water content in their stored nectar, so its sugar content preserves it for the winter. In spite of the humidity generated by evaporation, bees still need to collect water from cooling the hive and sustaining adult bees. (Fanning is hard work!) This is why you see a lot of drowned bees in your swimming pool, dog dishes, and water features.
Provide a water source just for your bugs (and toads, if you're lucky enough to have them around). Put a pan of pea gravel under a garden spigot, and keep it filled. For some reason, bees like a pinch of salt in their water (or pee, according to some old-timey beekeepers, but hey...you do you). If you have bird baths or water features, create a "rescue ramp" out of a flat stick so bugs can climb out.