Aster Purple Dome

Symphyotrichum novae-angliae 'Purple Dome' (Aster)

Aster ‘Purple Dome’ in September 2011, caged for rabbit protection; 40% ETo. Photo SK Reid.

Summary

Like other Michaelmas daisies, ‘Purple Dome’ is an herbaceous perennial that dies to the ground in late fall/early winter and the only maintenance required is an annual cutting to the ground at this time. In the irrigation trials, the plant performed adequately on all irrigation levels, but best on moderate irrigation and above. The relative growth for all treatments was similar with the only significant difference between the lowest and highest rates of irrigation (20% and 80% of ETo). Though the differences in quality ratings were small, the 20% ETo treatments scored consistently lower than the other three treatments, and would not be recommended.

Although the leaves tend to be bothered by spider mites late into the hot summer, the flowering of the plant is so profuse that the leaves cannot even be seen when in full bloom.  They also have a tendency to have chlorotic leaves at the base of the stems, which can be unattractive until the plant blooms. This is sometimes reflected in a poor leaf quality rating, but a high overall appearance rating. This plant was devoured by rabbits that worked their way under the field fence the first spring after planting; each plant was subsequently caged for the duration of the trials.

Master Gardener leaf quality ratings were sometimes taken at the end of the season as the leaves began to turn yellow, and annual average ratings for leaf quality as well as overall averages, are sometimes lower than they might otherwise be. The three counties that did not recommend this plant for their area, Alameda, coastal San Diego, and Riverside, all cited rabbit damage as their main issue.  Of course, this is a site specific objection, rather than regional.  The largest size achieved at the end of two years in the demonstration gardens was 21” high by 24” wide, making it a good choice for small gardens. It does slowly spread to make larger patches of this cheerful late summer into fall bloomer.

Growth and Quality Data

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Aster 'Purple Dome' closeup. Photo SK Reid.