As summer draws to a close, gardens can start to look a little ragged. Iris are long past their prime, and lilies have lost their blooms. Roses have developed blackspot, and delphinium lean dangerously close to the ground with not a flower in sight. No wonder my spirits soar at the sight of the tall, bronze stems of Helenium, stars of purple aster and golden rays of Heliopsis and black-eyed Susans (Rudbeckia hirta). Fall-blooming perennials add life to the flower border when our enthusiasm is flagging and nature is heading into winter.
Greg Bonovetz’s Duluth, Minnesota, garden comes into its own in autumn. Bees buzz among bright red blossoms of Monarda and sturdy stems of purple coneflower (Echinacea purpurea) contrast with ferny foliage and fine flowers of yarrow (Achillea species) and velvety leaves and trumpet-shaped flowers of Datura. White coneflowers blend with ‘Joan Senior,’ a creamy white daylily that blooms for six weeks.
A tall obelisk covered with pink flowers and shiny foliage of mandevilla makes a striking statement in the center of one bed, and spikes of Nicotiana sylvestris add a stately presence. ‘Stargazer’ lilies border another bed, their perfume pleasant in the morning air.
“One of the reasons I plant Oriental lilies is for the scent,” Bonovetz says, “and they look good when everything else is fading.”
Bonovetz extends his gardening season by using long-blooming annuals such as geraniums, marigolds, petunias and daturas and by mixing annuals and perennials in containers.
Landscape designer Ellen Zachos often gardens in Zone 7 on New York City terraces and balconies.
“A lot of the work for my clients is in large containers,” Zachos says, “and for most of my color, I rely on annuals because so much of the root space in these containers is taken up by trees and shrubs.” Among her favorite annuals are Scaevola aemula, lantana (Lantana camara) and torenia (Torenia fournieri). Scaevola blooms in New York right up to Thanksgiving, and it will survive temperatures down into the 30s. While it is invasive in some parts of the country, lantana is a great annual when grown beyond its hardiness zone. It never self-seeds, continues to do well without deadheading and blooms until the end of the gardening season. Zachos uses torenia, the wishbone plant, for shady spots.
In my garden, tall ‘Carmencita’ castor beans (Ricinus communis) look almost tropical with their dark maroon, maple-like leaves and fuzzy red seedheads. Bright orange Tithonia rotundiflora ‘Fiesta del Sol’ flowers contrast nicely with the burgundy tassels of ‘Love Lies Bleeding’ amaranth (Amaranthus caudatus) and airy stems and delicate lavender flowers of Verbena bonariensis. Tall ‘Van Gogh’ and ‘Moulin Rouge’ pollenless sunflowers surround the vegetable garden, ideal for fall bouquets.
Jo-Anne van der Berg-Ohms, of John Scheepers Inc. in Connecticut, has several favorite fall annuals. “Cleomes (Cleome hasslerana) are easy-growing, carefree flowers that can hold up to late summer heat spells and droughts,” she says. “Nasturtiums (Tropaeolum majus) give an opulent lushness to the early fall garden when other plants start to look a bit tired.” Van der Berg-Ohms uses coleus (Solenostemon scutellarioides) to fill in containers, and she often grows ornamental kale to use as a fall replacement for worn-out summer plants.
Some of my favorite perennials are just reaching their zenith in late summer and early fall. Ligularias (Ligularia dentata) light up shady spots with their almost-black rubbery leaves and golden flower clusters. My favorites are ‘Britt-Marie Crawford,’ ‘Desdemona’ and ‘Othello.’ Feathery flowers of western meadow rue (Thalictrum occidentale) provide a great backdrop for ‘Bishop of Llandoff’ dahlia, with its dark purple foliage and deep red flowers. Spires of sweet-scented black snakeroot (Actea or Cimicifuga) pair well with chartreuse foliage of the biennial feverfew (Tanacetum parthenium), and anise hyssop (Agastache foeniculm) is a magnet for Monarch butterflies.
In her southeastern Pennsylvania garden, Nancy Ondra, author of the book Fallscaping, relies on long-blooming perennials like Shasta daisy (Leucanthemum), coreopsis (Coreopsis lanceolata) and perennial sages (Sage officinalis) that start flowering in summer and keep going into the fall and those like asters (Asteraceae), boltonias (Boltonia asteroides) and Joe-Pye weeds (Eupatorium purpurea) that rebloom in fall if you cut them back after their first round of summer flowers.
For more advice on selective pruning and pinching back perennials, see Tracy DiSabato-Aust’s book The Well-Tended Perennial Garden. Deadheading religiously also prolongs the bloom season of many flowers.
Ondra also likes Sedum spectabile, monkshood (Aconitum carmichaelii) and goldenrod ‘Fireworks’ (Solidago rugosa) because they start in late summer and keep going into autumn. For autumn foliage color, she suggests ‘Angelina’ sedum, Tiarella and Heucheras. Both Ondra and Zachos mention Amsonia hubrectii with fine, threadlike foliage that turns brilliant yellow in autumn. Zachos plans to use it as a companion for red globe amaranth (Gomphrena globosa). She also likes Rex begonias (Rex cultorum), often thought of as houseplants, for their dramatic leaves. She pots them up and brings them indoors at the end of the season.
One of Ondra’s favorite tips is to wait until midsummer to sow or transplant annual flowers like California poppies (Eschscholzia californica), cosmos (Cosmos sulphureus) and cleome so they will peak in early fall.
“These annuals, along with the later-flowering tender perennials, add a fresh look at a time when most people think of the garden as tired and fading,” she says. “Another perennial that doesn’t come into its own until late September or early October is Mexican sage (Salvia leucantha).”
Grasses, vines and seedheads
Ornamental grasses are in their full glory in fall, adding texture and motion to the scene, and many can be left standing for winter interest. With colors of russets, gold, yellow and straw, they are especially effective backlit by the sun when it’s low in the sky.
Vines aren’t to be dismissed when it comes to fall color. Virginia creeper (Parthenocissus quinquefolia) covers the walls of our greenhouse in the fall with its deep orange to purple leaves. Other vines to consider are bittersweet (Celastrus scandens) for its bright orange berries, autumn clematis (Clematis terniflora) that blooms late with a blanket of fragrant white flowers and ‘Dropmore Scarlet’ honeysuckle (Lonicera nitida) that blooms all season long with intense orange blossoms. Attractive annual vines include my favorite ‘Heavenly Blue’ morning glories (Ipomoea violacea), hyacinth bean (Lablab purpureus) with its clusters of purplish-pink flowers and flat, deep purple seedpods, passionflower (Passiflora incarnate) and cathedral bells (Cobaea scandens).
Noel Kingsbury’s book, Seedheads in the Garden, demonstrates the role seedheads play in the late summer as a backdrop for fading flowers, a companion for grasses and native plants and a contribution to wildlife. Think rugosa rose hips, ‘Black Pearl’ ornamental peppers, flat saucers of achillea, cocoa-colored cones of rudbeckia (Rudbeckia hirta), blue-green poppy pods, and the balloon-like seedpods of love-in-a-puff (Cardiospermum halicacabum) and love-in-the-mist (Nigella damascena).
In northern hardiness zones, it takes time for tropicals to mature, but they are always worth the wait. Tall canna lilies, like ‘Pretoria,’ with striped leaves, water-loving elephant ears (Colocasia and Alocasia) like ‘Black Magic,’ caladiums (Caladium bicolor), ornamental bananas (Musafolia), Cordyline, Agave, Hibiscus and Brugmansia bring a touch of paradise into our Midwest garden.
Trees and shrubs
Northern Minnesota is known for its brilliant fall color, and we’re fortunate to have maples, oaks, poplars, birches and dogwoods on our property. The assortment turns our woods into a kaleidoscope of colors from yellow to orange to red to deep purple in autumn. In addition to their dazzling foliage, many trees and shrubs, including dogwoods (Cornus), elderberry (Sambucus), Viburnum, winterberry (Ilex verticillata), sumac (Rhus typhina) and mountain ash (Sorbus americana), have attractive berries that feed birds through the winter.
Michigan landscape architect Maureen Parker favors serviceberry (Amelanchier canadensis), ‘Pinky Winky’ hydrangea (Hydrangea paniculata) and ‘Tiger Eyes’ cutleaf sumac for fall color. A particular favorite of Ondra’s among the late-flowering trees is seven-sons flower (Heptacodium miconoides) for Zones 4 through 8.
“Its clustered, creamy white fragrant blooms open in late summer to early fall,” she says. “After they drop, the remaining flowerlike calyces turn bright reddish pink, making it look like the tree is blooming for a second time through the fall months.”
Ellen Zachos recommends ‘Kousa’ dogwood because it has large fruit, great reddish fall color and is less prone to anthracnose disease than native dogwoods. She also likes the sourwood tree (Oxydendrum arboreum) – a small Zone 5 tree with beautiful white flowers in the spring and vibrant red foliage in fall – and redbud for its bright yellow leaves.
With such a variety of plant choices and techniques available to prolong the gardening season, there’s no need to despair when fall rolls around. Start looking at your landscape with new eyes, and you’ll see beauty all around as you take care of fall chores.
Margaret Haapoja keeps the color in the fall garden at her home in Bovey, Minnesota.