Asters or Mums for Zone 3

New York Asters

• The hardy aster for which the widest number of types is available, New York aster (Aster novi-belgii) obviously originated here in the U.S. It was, however, welcomed with open arms by British breeders, who renamed it the Michaelmas daisy and churned out scores of cultivars which are survivors in U.S. Department of Agriculture plant hardiness zones 3 to 9. They include characters as unlike as the flamboyant 3-foot purplish-red Aster novi-belgii "Ernest Ballard" and the more restrained 1-foot pale lavender Aster novi-belgii "Audrey."

Other Zone 3 Asters

• Although the New York aster offers the widest number of options, a sprinkling of other aster species are also hardy in USDA zones 3 to 9. Those include alpine aster (Aster alpinus), blue wood aster (Aster cordifolius), white wood aster (Aster divaricatus), stiff aster (Aster linariifolius) and flat-topped aster (Aster umbellatus). Not all of their descendants may be as vigorous, but it is worth trying any interesting cultivars that have these names in their pedigree -- such as Aster alpinus "Dark Beauty," hardy in USDA zones 3 to 8, and Aster alpinus "Goliath," hardy in USDA zones 2 to 9.

Mammoth Chrysanthemums

• Mammoth chrysanthemums are so large that they are sometime called shrub-type mums. They originated at the University of Minnesota, where it was necessary that they be tough to survive, and were first released as the Maxi-mums and My Favorite series. With their name later changed to Mammoth to reflect their size, they are average in stature their first year, but the strongest of them can reach 3 feet in height and 5 feet across in subsequent seasons. A majority of those shrub types have “daisy” in their name -- such as “Coral Daisy,” “Dark Bronze Daisy” and “Red Daisy” -- and are perennial in USDA zones 3 to 9. The university has since produced a wide variety of other hardy mums. Gardeners in zone 3 should favor those listed as “early,” since they are more likely to bloom before heavy frosts.

Daisy Chrysanthemums

• Some of the hardiest chrysanthemums are those that look like color-added daisies. Chrysanthemum x morifolium “Sheffield Pink” sports 3-inch blooms in apricot pink. The similar Chrysanthemum x morifolium “Cambodian Queen” settles for just pink, and Chrysanthemum x morifolium “J. C. Weigelan” cranks up both the contrast and size with 3 1/2-inch magenta blooms. All are hardy in USDA zones 3 to 7. The genus name Dendranthema is sometimes substituted for Chrysanthemum and the species name x grandiflorum for x morifolium.