Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
8/16/99
Contacts:
Cindy Haynes, Horticulture Extension, (515) 294-4006,
chaynes@iastate.edu
Elaine Edwards, Extension Communication Systems, (515)
294-5168, eedwards@iastate.edu
Yard and Garden Column for the Week Beginning Aug. 20
More than Mums
By Cindy Haynes
Extension horticulturist
Iowa State University Extension
Many plants in the garden slowly wind down as summer slips away. However, the end of summer doesn't have to signal the end of the bloom period in your garden. Chrysanthemums are considered the quintessential queens of the fall-blooming perennial garden. However, many times these autumnal beauties do not reappear in the spring and replanting them every year can become a royal pain. But wait! There are several other excellent fall blooming perennials. These perennials are more reliably cold hardy than mums and will hold court with equal royal presence.
The New York Asters (Aster novi-belgii) can easily replace mums in the landscape. They are available in a wide range of flower colors and sizes. Flowering begins in August with colors ranging from white, pink, red, and lilac, to purple on plants from 2 to 5 feet tall. Pinching the plants back in spring and early summer creates compact plants with additional flowers. Powdery mildew is often a problem, especially in shady areas and sites with poor air circulation.
Another staple in the late season perennial buffet is Autumn Joy Sedum (Sedum 'Autumn Joy'). As the name implies, this 1- to 3-foot beauty begins blooming in August and continues into fall. The flower heads mature to a dark pink. This is also a great perennial for the winter garden as the flowers eventually turn brown but will continue to stand during most of the winter. This sedum prefers full sun to part shade with a well-drained soil.
Black-eyed Susan (Rudbeckia spp.) is an exceptional late season bloomer that starts in July and will continue for months into the fall. This perennial is bright enough to attract attention from great distances, which is why it is often used in roadside plantings. An outstanding variety is 'Goldstrum' Rudbeckia. It was chosen as the 1999 Perennial Plant of the Year by the Perennial Plant Association. The height of 'Goldstrum' Rudbeckia, as well as many other Black-eyed Susans, ranges from 2 to 3 feet. Black-eyed Susans prefer full sun with a well-drained soil.
For a perennial that is popular in European gardens try Goldenrod (Solidago spp.). This is not a joke! Goldenrod is a wonderful late blooming perennial. Unfortunately, Goldenrod has gotten a bad rap because it blooms at the same time as ragweed. Ragweed is the source of hayfever problems, not Goldenrod. Try this bright golden flowered perennial (1- to 3-feet tall) in your garden and breathe easy. Goldenrods prefer full sun and a well-drained soil.
For a little blue and gray this fall, try Russian Sage (Perovskia atriplicifolia). This 3 to 4 foot perennial has silvery-gray foliage topped with bluish-lavender flowers that start in July or August. The foliage has a distinctively sage-like fragrance. Since plants become floppy in shade, full sun is best. Russian Sage also requires a well-drained soil.
Another sun loving perennial for fall bloom is Obedient Plant (Physostegia virginiana). The bright pink or white flowers begin in August and continue into fall. This durable 2- to 4-foot-tall plant has few pest or disease problems. However, contrary to its common name, this plant is not very obedient and will wander in the garden.
Boltonia (Boltonia asteroides) is a tall blooming perennial that can be literally covered in tiny white or pinkish-lilac, daisy-like flowers beginning in July or August. The 3- to 6-foot-tall plants often require staking from the weight of the flower masses. 'Snowbank', a shorter (3 to 4 foot) variety, is more self-supporting. Plants prefer full sun and are tolerant of diverse soil types.
There are several ornamental grasses that flower in late summer and into fall. The feathery plumes of Maiden or Chinese Silver Grass (Miscanthus sinensis cultivars), Hardy Pampas Grass (Erianthus ravennae), Perennial Fountain Grass (Pennisetum alopecuroides), and Northern Sea Oats (Chasmanthium latifolium) provide a lot of grace and beauty to the fall and winter garden. After these 2 to 8 foot perennials die in late fall, their tall tan-colored leaves and plumes remain standing and blow gracefully in the winter winds. Most ornamental grasses prefer full sun and well-drained soils.
For a few late-blooming perennials for the shade, try Monkshood (Aconitum napellus), Toadlily (Tricyrtis sp.) or Turtlehead (Chelone lyonii). Monkshood is a stately 3 to 5 foot perennial with blue, lavender, or white flowers beginning in August. The flowers resemble a monks hood hence the common name. This perennial prefers a moist, fertile, well-drained soil in part shade. Since all parts of monkshood are poisonous, individuals with small children may want to plant other perennials.
Toadlily has an unusual white flower often marked with tiny purple spots. The flowers can occur at the tops of the stems or all along the stems toward the top. The flowers resemble tiny orchids and don't appear until late August or September. Plants range in height from 2 to 4 feet and prefer part shade and a fertile, well-drained soil.
Upon close inspection, Turtlehead is another appropriately named perennial. The bright pink flowers resemble a turtle's head and begin blooming in late July. This 3- to 4- foot-tall perennial prefers partial shade and a moist soil. There are white blooming species as well.
Several other perennials will light up your garden in late summer and fall like Bigleaf Goldenray (Ligularia dentata), Fleabane (Erigeron hybrids), Sneezeweed (Helenium hybrids), False Sunflower (Heliopsis helianthoides var. scabra), Japanese Anemone (Anemone japonica), Joe-pye Weed (Eupatorium purpureum), and Bugbane (Cimicifuga simplex). With such a variety of plants available for fall bloom, keep the mums in containers next to the front door.
ml: isugarden
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