Growing Asters: Fall Color for Your Garden and Wildlife
Asters are composite, star-shaped flowers that bloom from mid-August into October, offering colors from white and pink to blue and purple. They're one of the most important late-season nectar sources for pollinators in the mid-Atlantic.
Aster Varieties and Growing Zones
Asters are hardy in zones 3 to 8 and grow anywhere from 8 inches to 8 feet tall, and 8 inches to 4 feet wide, depending on the variety. There are over 180 varieties of asters. When DNA studies were done, many of the plants commonly called asters were reclassified under the genus Symphyotrichum.
You can shop flower seed options, including aster varieties, in our Garden department.
Sun, Soil, and Water Needs
In warmer southern climates, asters perform better with some protection from hot, intense mid-day sun. They flower best in full sun, with the exception of woodland asters, which prefer shade. Asters like loamy soil and benefit from watering during a drought. If your beds need amending, browse our soil and amendments selection to build the loamy base asters prefer.
How to Care for Asters
If your asters are getting too tall, pinch off the leaders. This keeps them shorter and helps prevent the flopping over that taller varieties are prone to. Asters flower best when divided every 2 to 3 years: lift the entire plant and divide it into 2 to 3 smaller clumps. If you let your asters go to seed, the flower color of the seedlings may not match the original plant.
For hand tools and supplies to make dividing and pinching easier, check our garden supplies collection.
Preventing Powdery Mildew
One common issue with asters is powdery mildew, which develops when the plants grow too thick, especially in the mid-Atlantic climate. Keep plants divided and spaced for good air circulation to help prevent this. If mildew has already taken hold, our weed, disease, and pest collection has treatment options, or stop by and talk to a team member for a recommendation suited to your garden.
Asters as a Wildlife and Pollinator Resource
Many of the later-blooming aster varieties are frost-hardy and will hold their color well after the first frost. In winter, finches and chickadees rely on aster seed heads as a food source, and you can often spot them foraging for larvae in the plant debris around asters.
If you want to extend that winter food source beyond what your asters provide naturally, browse our wild bird seed selection, or visit our Wild Bird Blog for more on feeding finches and chickadees through the colder months.
[Note: cross-links Garden content into the Wild Bird content cluster, good for topical authority and keeps readers on site longer]
When to Fertilize Asters
Fertilize asters in spring only. They set flowers in fall in response to shorter days, so you don't want to encourage new leaf growth heading into that season. See our fertilizer and lime options for spring feeding.
Why Grow Asters
Asters are a tough, reliable garden plant that offer late-season color and serve as an important late source of food for pollinators and wildlife.
For more seasonal growing tips, visit the Garden Blog.
FAQ: Growing Asters
When do asters bloom?
Asters typically bloom from mid-August through October, depending on the variety.
How tall do asters grow?
Asters range from 8 inches to 8 feet tall and 8 inches to 4 feet wide, depending on the variety.
How often should asters be divided?
Divide asters every 2 to 3 years by lifting the plant and splitting it into 2 to 3 smaller clumps.
Are asters good for pollinators?
Yes. Asters are one of the most important late-season nectar sources for pollinators, and their seed heads feed birds like finches and chickadees through winter.
