Asters bring fall color and pollinators
Are you looking to add fall color to your garden? Perhaps you want to add more native plants to support pollinators and other wildlife? Asters are the perfect choice to accomplish both goals.
Asters are perennial flowering plants that bloom in late summer and fall, often until frost. Many varieties are native to Pennsylvania and are adaptable to various growing conditions.
There are countless ecological benefits from asters. These perennials provide a critical source of nectar and pollen for pollinators after most plants have started to fade. They are especially important for monarch butterflies (Danaus plexippus) by providing nectar during their long-distance migration.
Asters also serve as the host plant to over 100 species of butterfly and moth caterpillars, such as the pearl crescent (Phyciodes tharos) and silvery checkerspot (Chlosyne nycteis) butterflies.
In turn, the caterpillars become an essential food source for wild birds.
Like many native plants, asters require little care once planted in the proper location and given time to establish. Here are a few adaptable species that you can incorporate into your garden:
New England aster (Symphyotrichum novae-angilae) is a stunning species that can grow up to 6 feet in height with a 2- to 3-foot spread. It produces several sturdy, erect stems that are encircled by narrow, hairy, oblong leaves that grow up to 4 inches.
This aster blooms in August through frost, bearing purple petals surrounding yellow centers. New England aster grows well in partial to full sun, with moist to well-drained soil.
If height becomes an issue, cut back the stems in May or June to encourage branching and form a shorter and more compact plant. As the plant matures and begins to flower, its lower leaves turn brown, so plant shorter perennials in front of New England aster to hide the unsightly lower branches.
Aromatic Aster (Symphyotrichum oblongifolium) grows to 2 feet in height with a 3-foot spread. Stems are stiff and woody; leaves are grayish-green, oblong, and up to 4 inches long. The flowers are lavender to purple and are about 1 inch in diameter. Aromatic aster is a drought-tolerant species, making it an excellent choice for dry and sunny sites with poor, rocky soil.
It blooms September through November, making it one of the latest blooming asters. This aster forms small colonies from underground rhizomes.
White wood aster (Eurybia divaricata) grows in partial to full shade and reaches 2 to 3 feet in height with an equal spread. It has white blooms from August through October. White wood aster spreads by underground rhizomes and can form dense colonies that can act as a groundcover. This, too, is a drought tolerant species.
Blue wood aster (Symphyotrichum cordifolium) is another drought-tolerant species that performs well in the shade. Also known as heartleaf aster, this species has heart-shaped leaves growing up to 5 inches long.
The plant is covered in daisy-like flowers with yellow centers and pale blue petals in September and October. The heads are produced in profusion but are only 1-half inch in diameter. The centers turn maroon with maturity. Blue wood aster grows 2- to 3-feet tall with an equal spread in average, dry, or moist soil. Flowering is best with at least three hours of sun exposure. Blue wood aster forms small colonies from underground rhizomes and tends to self-seed.
Asters are a valuable addition to perennial gardens. Their beauty, hardiness and importance to pollinators make them a beneficial contributor to the environment.
Penn State Extension has information about asters (https://extension.psu.edu/rain-garden-plants-new-england-aster) and aster diseases (https://extension.psu.edu/aster-diseases). If you have questions about asters, call the Butler County Master Gardener Garden Hotline at 724-287-4761, ext. 7, or email the Master Gardeners at butlermg@psu.edu.
Amanda McWilliams is a Penn State Extension Butler County Master Gardener.
