Gardening Articles: Flowers :: Perennials
by Rick Darke
How many perennials do you know that offer delicate blossoms in spring, outstanding color in autumn, freedom from pests and diseases, and extraordinary tolerance to cold, heat, and drought? And how many of these are easy to grow and propagate, and can go up to 20 years without needing to be divided?
Blue star (Amsonia), so called for its tiny starlike flowers, fits the bill perfectly. There's no doubt that this beautiful and diverse group of herbaceous perennials deserves more attention.
My wife, Melinda, and I garden on 1-1/2 acres in Pennsylvania, and the blue stars add immeasurably to our landscape's multiseason appeal. Their modest demands fit our main purpose: to enjoy the garden and share it with friends.
Nearly 20 species of blue star are native to parts of central, southern, and eastern North America; a few come from southern Europe, Asia Minor, and Japan. They are outstanding perennials in most of this country, especially in hot-summer regions. They can be grown in the Pacific Northwest, but the relative lack of sun and warmth there somewhat diminishes their vigor and autumn color.
Soil and moisture preferences vary by species, but most prefer full sun or partial shade. Nearly all are hardy to USDA Hardiness Zone 4 (many to zone 3), and the majority thrive in areas as warm as zone 9.
Each year, we delight in cutting blue stars for fresh flowers in spring and golden foliage in autumn. Blue stars are related to dogbanes (Apocynum), oleander (Nerium), and periwinkles (Vinca), and produce a similarly milky sap which can be messy. To reduce the mess, you can dip the cut stems into boiling water or sear them in a flame before placing them in arrangements.
Flowers and Foliage
All blue stars produce flower clusters at the tops of the stems in spring or summer. Individual flowers are typically 1/2 inch across with sharp-pointed petals. Color ranges from deep periwinkle blue in bud to light sky blue in bloom.
Foliage varies tremendously. Some species have broad, medium-textured leaves, others finer than lawn grasses. The brilliant gold tones of their autumn foliage frequently rival the fall displays of trees and shrubs. Height varies from less than a foot to more than 3 feet, making some species useful as ground covers and others as deciduous hedging.