Those who grow Michaelmas daisies look forward to their flowers with great anticipation. Though their sheer gaiety is always appealing, many gardeners have not accepted them as the prime perennial for color and interest in the garden before the hardy chrysanthemums break into bloom.
Judging from experiences at the Royal Botanical Gardens, Hamilton, Canada, where Michaelmas daisies were displayed to the public for the first time in 1955, this situation will change. The majority of visitors were not aware of their existence.
However, they liked what had been done to improve the native New England and New York asters, including the range of color — white, pink, lavender, purple, blue, and red — and the many variations of size and habit. Who knows, they may vet gain the favor and prestige they enjoy in Britain!
This article will not deal with the entire group of hardy asters but with the late summer and early autumn flowering varieties. The attractive English name, Michaelmas daisy, was adopted because many bloom around the time of the Feast of St. Michael, which falls on September 29.
Michaelmas daisies are easy to grow. They require plenty of sunlight and do better on medium to heavy Mains. They are not successful on dry sites and droughty soils, and during dry periods will benefit from occasional soakings since they need plenty of moisture.
New plants are usually purchased as rooted cuttings, although occasionally as field-grown divisions. When given sufficient space, they produce a more outstanding display if grown in clumps of three, five, or more plants in large borders of one variety, spacing them 12″ to 15″ apart.
Within a year or two, clumps will become solid, and after two or three years, divide them, replanting divisions from the outer edges of the clusters. In fact, as with chrysanthemums, they can be divided every year, though unlike them, they cannot be moved elsewhere when in bloom.
Problem With Hardy Asters
One problem with hardy asters is their susceptibility to mildew, which varies with the variety and season. At a minimum in open plantings, mildew affects the appearance of the foliage, and when severe, the majority of the leaves wither and cease functioning before flowering time. Pedicels and even flowers may also be affected.
The tarnished plant bug and the lace bug are the most troublesome among insects. These are stinging and sucking insects that puncture and distort foliage and are active throughout the summer. A combination spray or dust, such as wettable DDT and captan, is an effective control measure.
Most Michaelmas daisies have been derived from two North American species, the New York aster (Aster Novi-belgi) and the New England aster (Aster novae-angliae). The Italian aster (Aster amellus) varieties are highly regarded in Britain.
Still, they have not proved permanent in the collection at Hamilton, where derivatives of the American species are hardier. The season starts in late August or early September. Mid-season varieties flower towards the middle of September, with the late continuing into early October.
Traditionally most Michaelmas daisies are grouped as novae-angliae and Novi-belgi types. The former are known for their narrow ray florets and how the bracts of the involucre arc are oriented upward, giving a somewhat fuzzy appearance to the inflorescence, especially before and as the flowers are opening.
The foliage is hairy and lacks the distinctive smooth appearance characteristic of the other leading group.
New England Varieties
For years, those who have grown Michaelmas daisies will remember three older New England varieties — Barr’s Pink deep rose slightly dulled with purple. Harrington’s Pink, bright clear pink, and Ryecroft Purple. All reach three feet or more in height.
Two newer additions include the strong growing Survivor, a tall bright pink and the latest flower, and Incomparabilis, an intense fuchsia-red variety, which flowers in mid-season and reaches 30″ to 36″. The flower diameter in this group ranges between 1 1/4″ to 1 1/2″.
Most of the outstanding garden varieties have Aster Novi-belgi ancestry. The cushion types are 12″ to 15″ tall and 24″ or more inches wide. Notable are four early-flowering varieties, beneficial for front border positions, with abundant flowers that measure 1 1/4 inches in diameter.
Pacific Amaranth occurs first, with irregular rich purple masses of bloom that smother plants. Of the four, it is the least susceptible to mildew. Pacific Horizon develops a similar habit, but the light blue flowers are not so long-lasting.
Princess Margaret Rose, a rose counterpart, dulled somewhat with purple, always makes a good showing, while Purple Feather is another handsome purple-flowered cushion type that is greatly admired. The rose Twinkle and the prostrate blue-violet Violet Carpet are now being watched with interest.
Among the intermediates are a series of delightful varieties. These average about two feet in height, though some grow 30″ and others less than 18″ tall. In this group are the mid-season varieties, like the lovely blue-violet Eventide, an English variety, an aristocrat among hardy asters, with semi-double, 1 3/4 inch flowers, carried in great abundance.
Eventide intends to replace Violetta, who was the best in this color class, though taller and bushier. Another relative newcomer from England, Janet McMullen, is a close second. It boasts the most extensive and showiest flowers of any variety in our collection, with abundant clear pink flowers up to 2 1/2 across. Stems are not sufficiently strong to support the heavy blooms that require staking.
Red asters have their admirers, and in the intermediate group, three varieties are recommended, all having rather small flowers, 1 1/4″ in diameter, appearing in great profusion. All have the same small leaves, which frequently mildew badly. Beechwood Challenger is the old standby, but Beechwood Beacon is brighter.
Winston Churchill is the reddest, but there has been some difficulty in wintering it here. A further trial is needed before stating that it is less hardy than others.
English Varieties
Medium-sized English varieties include Prosperity, Peace, and Plenty. Prosperity is the best performer, a much-branched, bushy kind, with small 1 1/4″ inch flowers of bright pink. It is also suitable for cutting. Peace has large two-inch, semi-double lavender flowers, and plenty, though similar, is more desirable for its large, medium blue flowers.
White Michaelmas daisies are helpful in the garden, primarily when used as a foil for a variety like Eventide. Like Perry’s White and White Ladies, many whites show a distinct purple discoloration in the center as the anthers mature, which detracts from the purity of the blooms.
The Arctic proved to be the best white in this group of intermediates, midi pure white florets, 1 3/4″ across, with yellow centers.
Among the tallest in the group are the late-flowering white Mt. Everest and the old favorite light blue Climax, which mildews badly, yet plays its part with Survivor at the end of the season.
Gardeners often wonder if it is worth giving space all season to plants that flower for a few weeks in September. The answer is that a healthy Michaelmas daisy is as attractive in midsummer as most plants coming into bloom or as many perennials that have finished flowering.
In addition, they fill the gap before chrysanthemums and are there to greet you when you return from your late summer vacation.
44659 by Leslie Laking