Several commonly-planted perennial landscape bushes and shrubs need a regular winter cleanup or pruning to look their best during the following bloom season. Buddleja, most of the sages and carpet roses, all sold as easy-care drought- and heat-tolerant plants, are often left to grow unchecked for many years until they lose shape, stop flowering or grow too large for the space.
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Buddleja (sometimes spelled buddleia), is also known as butterfly bush because its flowers are so very attractive to butterflies. Taller varieties of butterfly bush can grow to 10 feet high and wide within just a few years. The multiple trunks and woody branches get tangled, rangy and look rank without hard winter pruning every year. Cut all the trunks back to 8 to 10 inches high (on dwarf varieties, as well) and thin out center growth and weak or crossing wood to the base or the ground. When established, butterfly bushes need little summer water (once a week will do except in the hottest weather) and little fertilization. Feed your butterfly bushes at the end of January with a cup of a low-number higher phosphorus granular fertilizer or a cup or two of good compost to help increase flower production.
The sage or salvia plant family has many members. Some, like autumn sage, Cleveland or California blue sage and Russian sage are hardy perennials with fairly long life spans. With a long flowering season and attractive, often scented foliage and flowers that provide pollen and nectar to a wide variety of pollinators, the sages are valuable landscape plants, well-suited to our climate. Perennial sages should be cut back to about 8 to 10 inches high each winter and, just like butterfly bushes, the remaining stems and branches should be thinned out. The secret to keeping sages in flower and looking fresh is to remove spent flower stalks throughout the bloom season.
Carpet roses are so hardy, pest- and disease-resistant that they can be used as ground covers in many spots where other plants will not thrive. They’ve even been used on highway medians although their thorny dense structure caught all sorts of litter and debris so that the roses eventually created blight instead of beauty. Shearing carpet roses annually with hedge clippers was recommended for many years, but many sheared roses suffer from unsightly dieback in the center of the bush. Although hybridizers have been working on reducing the number of sharp thorns on carpet roses, wear heavy gloves tackling carpet rose pruning. (Rose thorn injuries can cause serious infections when the thorns push dirt and bacteria into the wounds). Most carpet rose canes grow out of a whirl or circular pattern in the center of the low-lying bush. Remove any crossing canes and weak growth to clear the congested center and improve air circulation and allow sunlight to reach the interior.
Two spring-flowering shrubs are often pruned at the wrong time. Yellow-flowered forsythia and purple-flowered hebe should all be pruned after flowering in spring, before leaf set. Cut hebe branches back by a third to maintain a bushy shape. Prune a third of forsythia branches back to the ground and also remove weak or damaged branches.
Send Elinor Teague plant questions at firstname.lastname@example.org.