Growing Asters

Wednesday, September 09, 2015 0 Comments A+ a-



By  Alexis Amorese, Extension Horticulture Agent

If you are craving some color in your fall garden this year, try swapping out those mums for some beautiful Asters! These brilliant little flowers can brighten up your flower beds when little else is blooming. Aster, the Latin word for “star” is the perfect description for this Kentucky native, that blooms starting in late summer and can continue until heavy frost. In the past, asters have not been heavily used due to a weedy appearance, but with new cultivars now available, all gardeners will be happy with the smaller, mounding growth habits of these new varieties. 

Asters should be grown in full sun locations, and will tolerate most soil conditions. With their variety of colors, including white, pink, lavender, red and blue they are a honey bee and butterfly favorite. While also adding some unusual color interest in the landscape. Plant heights range from 8 inches to 8 feet, depending on variety. Taller varieties are lovely as backdrop plants, or to naturalize an area. Asters may spread aggressively with both rhizomes and seeds, so division may need to be done every 3 years to avoid over crowding issues.

It is best to plant these little beauties in the spring, with 1 to 3 feet spacing, depending on variety. After prepping your garden bed, consider adding 2-4 inches of compost, and don’t forget to take a soil test to your local County Extension Office before adding any fertilizer. Remember that with most plants, it is best for your planting hole to be twice the diameter of the root ball, but no deeper. The goal is to have the top of the root ball be level with the soil surface. Water thoroughly, keeping in mind that newly planted plants need extra water throughout their first growing season. After the first killing frost in fall, cut the stems back to an inch or two above the soil line.

Varieties to consider:

Aster azureus - Sky Blue Aster – This Kentucky native is small and well suited to a typical home landscape.

Aster novae-angliae – New England Aster – An aster that is native to Kentucky; consider ‘Alma Potschke’, ‘Purple Dome’, ‘September Ruby’ or other cultivars for your garden.

Aster oblongifolius – This aster is native to Kentucky; the selection ‘Raydon’s Favorite’ has been one of the best plants for flowering in late September and October.

Aster novi-belgii - Michaelmas Daisy, New York Aster - New York aster is native to Kentucky and is relatively common in open fields. In the garden fertilize sparingly and divide every other year. Taller types require staking. There are over 300 cultivars available. Consider other cultivars ‘Ada Ballard’, ‘Alert’, ‘Bonningdale White’, ‘White Swan’ and ‘Woods Purple’ for your garden.