Learn about asters, including how to plant and grow them.
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How to Grow: Asters
Bloom Period and Seasonal Color
late summer to fall in colors such as blue, purple, red, pink and white
Mature Height x Spread
1 to 6 feet x 2 to 4 feet
Native, attracts beneficials
This native wildflower is a sure sign of late summer and early fall in New England. You can see it blooming next to goldenrod along roadways, in abandoned fields, and in meadows. Cultivated varieties of the wild aster are easy to grow, yet have better plant form, larger and more varied flowers, and a better growth habit. The two main types are New York and New England asters. New England asters tend to have denser and frillier flowers than New York asters. The attractive, daisy-like, single or double flowers are a favorite of bees, butterflies and other pollinators. While many varieties can stand up to 6 feet tall, newer hybrids are shorter and bushier offering options for small space, and even container, gardeners.
Where, When and How to Plant
Asters are hardy throughout our region. Purchase plants from your local garden center and plant in spring to early fall. You can plant divisions from a friend or neighbor’s garden. Plant asters in full sun on compost-amended, well-drained soil. Asters don’t grow well on poorly drained, clay soils.
Keep new transplants well watered. Once established, asters are very carefree. Add compost around the base of plants each spring. Mulch to preserve soil moisture and prevent weed growth.
Regional Advice and Care
Divide plants in spring as needed. Pinch the tops of young shoots in spring to promote branching, more flowering and a shorter plant. Stake tall aster varieties to keep them from flopping over. Powdery mildew disease thrives during our humid summers and asters are susceptible. Look for white, then yellowing leaves in late summer. To avoid this disease, plant resistant varieties, water from the bottom to avoid wetting the leaves and plant in an airy location where leaves will dry quickly once wet. Cut back and clean up foliage in fall to prevent disease from overwintering near the plants.
Companion Planting and Design
Plant tall varieties in the back of flower gardens near earlier blooming perennials, such as daylilies and Shasta daisy, to provide a continuum of color into fall. Mix and match shorter varieties near earlier blooming, lower growing perennials, such as coreopsis and geraniums. Plant next to other late summer bloomers, such as Russian sage and ornamental grasses, for a colorful fall flower show.
“Purple Dome” is a dwarf, New England variety that grows less than 2 feet tall. “Alma Pötschke” is a New England aster that grows 4 feet tall with red flowers. “Professor Anton Kippenberg” is a New York aster that grows 1 to 2 feet tall with light blue flowers. “White Lady” is a New York type that grows 5 to 6 feet tall. “Patricia Ballard” is a New York aster that grows 2 to 3 feet tall with pale blue, double flowers.
Excerpted from my book, New England Getting Started Garden Guide.
Although we know it as a native in our country, the aster is a widely-grown perennial flower with a history intertwined with many cultures. It’s known as the Michaelmas daisy because its usually in full bloom on the Feast of St. Michael at the end of September. The people of Li, China were said to live well past 100 years due to drinking aster-flavored water. The Chippewa indians burned the dried aster root to attract game. Shaman’s would chew aster root to induce visions to see illnesses in patients. Most modern gardeners are more interested in the aster flowers and plant size than any folkloric uses. The two species most commonly grown in our area are the New York and New England aster. New York asters tend to grow 2 feet tall, while New England varieties grow 3 or more feet tall. New York asters also tend to be more susceptible to powdery mildew disease. Both species produce star-shaped flowers in colors such as white, pink, lavender, and red. The allure of the aster is the beautiful fall color. It blooms with goldenrods creating a perfect color combination from September until frost. They are also tough plants, surviving is USDA zone 3 and coming back consistently each year. Some good varieties to look out for are ‘Purple Dome’ with loads of lavender-colored flowers, ‘Alma Potschke’ with red flowers, and ‘Puff’, a nice white aster.
Asters grow best in full to part sun on moist, but well-drained soil. Stake tall varieties to prevent them from flopping over or pinch the tops of asters in July to stimulate a bushier, shorter plant. In spring every 3 to 4 years you may need to divide your asters if they have become large and unruly.
Now for this week’s tip, harvest your gourds, pumpkins and winter squash before a frost weakens their skins. Place them in a dry, warm area to cure and toughen up, then they will be ready for storage.
From the Vermont Garden Journal.