There’s more to fall color than the leaves of trees and shrubs. Hardy, late-season perennials offer blooms, fragrance and beauty just as the growing season winds down. From the common mum to the exotic fall crocus, here are five of the best perennials for flowers in your fall garden.
Aster
Asters are probably the second best-known plant for fall flowers. First is chrysanthemum. Even though asters often share the garden center bench with mums in fall, the best selections are planted in spring.
You’ll find small native aster plants in garden centers in spring. These are usually in four-inch pots. Buying asters this way is an act of faith and hope. Unlike the already flowering fall asters in garden centers, asters purchased in spring need to grow for several months before they bloom. You can also find asters for spring planting at many online retailers and mail-order catalogs.
There are 180 species of aster, along with hundreds of named varieties or cultivars, such as Raydon’s Favorite, October Skies or Purple Dome. North America is blessed with many native asters that are garden worthy.
Some of the best, however, are hybrids bred for long bloom times, larger flowers, disease resistance and other attributes. Asters are an important late-season perennial for migrating monarch butterflies and other pollinators. For humans, aster offers a light fragrance and a lovely cut flower. Popular common names include New England aster, Michaelmas daisy, aromatic aster and smooth aster.
Select your asters for color, bloom time, size and disease resistance. Grow in full sun and soil that doesn’t stay too wet. Mulch, making sure it does not touch the base of the plant. Water as needed throughout the summer. In early June, cut asters back by about one-third. This reins in the height and increases the number of flowers. You can cut them back another one-fourth to one-third again in late July or early August if flower buds have not formed.
In late winter or early spring, cut back the asters to a few inches from the ground. This would be the time to divide asters, too. Select for size, flower color, and bloom time.
Botanical name: Symphyotrichum sp
Plant type: Perennial
Flower color: Blue, purple, pink, white
Mature plant height: 8 inches to 5 feet, depending on the variety
Maintenance needs: Low
Blooming time: Late summer and early fall
Grows best with: Goldenrod, rudbeckia, amsonia
Ideal growing condition: Full sun, well-drained soil. Water as needed
USDA Hardiness Zones: 3-8
Autumn Bride coral bell
Coral bells bloom in spring and early summer, but the Autumn Bride variety blooms in August and September. When planted densely, it puts on quite a late-season show.
Autumn Bride is a member of the Heuchera family, a plant that is native only to North America. A no-fail, late-season native bloomer, its stalks of creamy white, bell-shaped flowers emerge from hand-size, dark green, toothed leaves. Tiny hairs give the leaves a velvety feel. The plant sometimes is referred to as hairy alum root.
Autumn Bride can be found in garden centers in spring and early summer. This perennial can be grown in shade or sun. If grown in the sun or in a hot climate, give it afternoon shade. It prefers rich soil, so mix in compost or other organic matter when planting. Once established, this flowering perennial is drought tolerant.
Autumn Bride (and many other coral bells) are evergreen or semi-evergreen, meaning they hold onto their leaves, depending on the harshness of the winter. In spring, snip off any winter-damaged leaves and cut back the flower stems to keep the plants neat. This plant may self-sow a bit, but it would not be considered aggressive. Divide or transplant in late spring to early summer.
Coral bells sometimes heave from the ground in winter. If that happens, gently push them back into the soil. This coral bell does not have any disease problems. However, if it’s kept too wet, crown or root rot may develop.
Botanical name: Heuchera villosa
Plant type: Perennial
Flower color: White
Mature plant height: 1 ½ to 3 feet
Maintenance needs: Low
Blooming time: Late summer and early fall
Grows best with: Hosta, ferns, asters
Ideal growing condition: Shade to part sun, rich organic soil
USDA Hardiness Zones: 3-8
Korean mums
Mums (short for chrysanthemum) are the most popular plant among fall flowers. Korean mums are the latest-blooming members of the family, and they look very different than their siblings found at garden centers in fall.
Fall mums are bred to bloom at that time. They also are pruned to their roundy-moundy, cushiony shape. They are considered a commodity plant and are treated as an annual by many gardeners. These can be planted in fall ornamental containers or plopped in a sunny landscape. If you want to winter them over, don’t cut them back until you see new growth at the base of the plant in spring. Spring is also the time to divide these plants.
Developed and bred by a Connecticut grower in the early 1900s, Korean mums’ daisy-like flowers start their show in late September and continue well into November. Korean mums can sometimes be found in garden centers in spring, but more likely you’ll find them in mail-order catalogs or at online retailers.
Plant Korean mums in spring in full sun and in well-drained, average, moist soil. No mum likes wet feet. Add mulch, but keep it away from the base of the plant. As with their cushiony siblings, allow Korean mums to remain upright through winter. Cut back in the spring. This is the time to divide the plants every two or three years, too. Select for flower color, size and bloom time.
As with asters, once mums get about 8 inches tall in spring, cut them back by one-half to one-third. Do that again around July 4 to rein in the height and increase flowers. All mums have an earthy fragrance. Cut some for long-lasting indoor arrangements.
Botanical name: Chrysanthemum sibiricum
Plant type: Perennial
Flower color: Red, apricot, pink, pale yellow, orange
Mature plant height: 3 to 4 feet
Maintenance needs: Low
Blooming time: Late summer and fall
Grows best with: Shrubs with fall color or as a drift in the bed
Ideal growing condition: Full sun, average, well-drained soil; water as needed.
USDA Hardiness Zones: 4-9
Rudbeckia
Rudbeckia is the family name for about 40 types of black-eyed Susans, as these plants are commonly called. Probably the most well-known is Goldsturm, a native plant sent decades ago to Europe for breeding and returned to us with a fancy name and perennial price tag.
Sometimes called yellow coneflowers, you can find rudbeckias in garden centers in spring and summer. They come in all sizes and flower colors. Some have yellow flowers or red petals with yellow tips around brown centers. Others have pale yellow petals around green centers. Some have unusual quilled flowers.
Depending on the variety, perennial flowers start blooming in late July or early August, well into September and early October. Pollinators regularly visit black-eyed Susans, a common plant in butterfly gardens.
Grow rudbeckias in full sun and average to poor soil. Soil that is too rich may cause this and other native perennials to flop. Black-eyed Susans sometimes have a faint anise scent. These perennials tend to have what’s called a good branching habit, which means there are lots of flowers to cut for long-lasting indoor arrangements.
Deadheading (removing dead flower heads) keeps the plant reblooming longer. It also reduces the plant’s habit of self-sowing. If there’s a drawback to some varieties of this plant (such as Goldsturm), it’s that it self-sows aggressively throughout the garden. Practice tough love and remove the seedlings where you don’t want them. Share them with friends, family, and neighbors. Divide or transplant in spring or early summer.
Another concern about rudbeckia is it sometimes gets powdery mildew and other leaf diseases. Select plants for their size, flower color, bloom time and disease resistance.
The Perennial Plant Association has named American Gold Rush Rudbeckia the 2023 Perennial Plant of the Year. The perennial has hairy leaves, making the plant resistant to septoria leaf spot, a common disease on some rudbeckia.
Botanical name: Rudbeckia spp.
Plant type: Perennial
Flower color: Yellow, red-yellow, brown-yellow
Mature plant height: 1 to 5-plus feet
Maintenance needs: Medium
Blooming time: Mid- to late summer into early fall
Grows best with: Butterfly bush, shrubs with fall color
Ideal growing condition: Full sun, average soil
USDA Hardiness Zones: 4-9
Autumn crocus
Autumn crocus (colchicum spp.) sends up 8- to 12-inch tall, green foliage in spring that goes dormant until late summer or early fall. Then, pink to white flowers appear. Some of the flowers are single and some have the ruffles of double blooms.
Plant autumn crocus bulb-like corms 4 to 6 inches deep in spring to midsummer to ensure roots get established before bloom time. Plant in a sunny to partly shady spot that is protected from hot sun in the afternoon. As a bonus, colchicum is deer resistant.
Autumn crocus is showiest when planted in clusters of at least three. Plant them among ground covers, in the perennial garden or in spaces left vacant by end-of-season annuals. They also work well in clusters between shrubs with fall colors.
You might be able to find these in garden centers, usually packaged rather than in bulk. You can also order them at online retailers specializing in bulbs. Popular varieties include Waterlily and Nancy Lindsay. There are several species of colchicum, all of which are low maintenance.
Autumn crocus is not a crocus at all. This fall-blooming, crocus-like bulb is deadly if eaten, so don’t confuse it with the spice-producing saffron crocus (C. sativus), sometimes also called autumn crocus.
Botanical name: Colchicum spp.
Plant type: Perennial bulb
Flower color: Pink, lilac, white
Mature plant height: 10 to 12 inches
Maintenance needs: Low
Blooming time: Mid- to late summer into early fall
Grows best with: Ground covers, shrubs with fall colors
Ideal growing conditions: Organically rich soil, afternoon shade
USDA Hardiness Zones: 4-8
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Main photo credit: Collage of the above photos (From L to R: Wikimedia | CC-BY-SA-2.5,2.0,1.0, Wikimedia | CC-BY-SA-3.0, manfredrichter | Pixabay, victoriaporter | Flickr, Jo Ellen Meyers Sharp )
