How do I Prune Asters, Salvia & Other Flowering Plants?
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Some seed heads, like these sea hollies, are very decorative.Name unknown image by Billy from Fotolia.com
Wait until the plants have finished blooming. Some plants, like New York asters, bloom in the fall. Others, like salvias or spring asters, bloom once in spring or summer and do not re-bloom without pruning. If you plan to harvest the seeds, wait until the seed heads have fully ripened. - 2
Pruning with hand trimmers can be time-consuming.cisaille image by Camanettes from Fotolia.com
Grasp handfuls of flower stalks just under the spent flower heads. Cut the plant down to two-thirds of the original height, removing the top third. Dispose of the unwanted seed heads. Save dry seeds in a dark, dry, cool location if desired. - 3
String trimmers are ideal for plants that hold their flowers high above the foliage, like this scabiosa.flower bed (selective focus) image by starush from Fotolia.com
Use a string trimmer or hedge trimmer for plants with smaller clusters of spent blooms. Plants that become top-heavy or become leggy after blooming benefit from this method. Remove the top third of growth, similar to hand-pruning. Rake and dispose of the cuttings. - 4
Hollyhocks are particularly vulnerable to disease.Hungry Bee on Hollyhock image by Vanessa Taylor from Fotolia.com
Allow insulating foliage to remain on the plant through the winter. Although many gardeners prefer cutting flowering plants to the ground in late fall or early winter, the North Carolina Cooperative Extension reveals that this reduces plant hardiness, actually harming the plants. Larry Hodgson, from "Perennials for Every Purpose," recommends only pruning disease-prone plants, like hollyhocks, to the ground in late fall. - 5). Prune any remaining stems in spring, to just above the plant crown. Do not remove the insulating, dead foliage until after the average last frost date, or the plant may put on new growth only to suffer cold-weather damage. Dispose of or compost the cuttings.
