Perennial Asters Increase in Varieties

The perennial aster has undergone considerable breeding in recent years and many new varieties are becoming available. This is a garden flower that has been slow to gain popularity in the United States. Asters are a native plant. Many of the native species grow as much as 5 to 6 feet tall and have a weedy appearance. Perhaps this is why gardeners have been slow to accept them. The name, aster, comes from a Latin word for ‘star’ and refers to the appearance of the individual flower.

It was in Europe, beginning in the 1890′s, that the original breeding of asters was done. There they were developed with larger flowers in some varieties or more recently into short, bushy plants suitable for modern gardens. Some of the improved varieties are tall enough to require staking, but they are free flowering and make good background plants. Asters make good companions with chrysanthemums. Asters are available in true blue, purple and pink colors while chrysanthemums provide the yellow, bronze and orange colors as well as lavender and pink. Both are available in white and a range of other shades.

Much of the short, bushy growth of asters was derived from the alpine aster and a few other low-growing species. Modern asters can become compact, rounded clumps that are similar in form to many of our modern chrysanthemum varieties. These asters are well suited to the rock garden, but also useful in the front of perennial borders. Exactly when asters and chrysanthemums will flower in the fall depends very much on summer weather. In a normal summer when weather is hot in July and August, asters will develop rapidly while garden mums will tend to be delayed. In such years, many aster varieties may flower 1 or 2 weeks earlier than many mum varieties. If the summer is cool and cloudy, the garden mums will often flower earlier than the asters which may be delayed one or two weeks. Asters, as well as mums, can tolerate light frost.

Asters are easy and durable plants for the hot, sunny location, but can grow in very light shade. Shade, however, easily makes them more leggy. Asters need good drainage and may be killed out during the winter if drainage is poor. Although they are easy to grow, they are subject to a few leaf diseases. These pests do not do serious damage to the plants, but can make the leaves unsightly. Some of the low, mounded forms produce so many flowers that much of the damaged foliage is hidden during flowering.

The most common leaf problem of asters is mildew. Rust may also sometimes appear. Wettable sulphur as a spray helps control rust if it becomes a problem. Copper fungicides are the most effective for mildew control of these plants. Another disease called aster yellows may also attack them and cause deformation of the plants. When this problem appears, dig out and destroy infected plants.

Many of our modern hybrids for the garden are derived from the New York aster, Aster novi-belgii and Aster ericoides. Another common perennial garden aster is the New England Aster, Aster novae-angliae, but it has been less used in modern hybrids. This is probably because most varieties of New England aster are somewhat taller. The flowers of New England asters tend to be somewhat larger than most others, but there is much variability between them.

Among some of the outstanding varieties that exist are Patricia Ballard for pink, Winston Churchill for Raspberry, Professor Kippenberg for dark blue and Schone Von Dietlikon for medium blue. These are low bushy varieties, but you will find many more in all heights, sizes, colors and shades. Asters are plants bound to continue to gain in popularity in future years.