A hint of spring came with the warmer weather. Snow piles quickly disappeared and the first green shoots of bulbs came through the ground. We know its early spring when snowdrops and snow crocus are blooming. This is a good time to prune those woody shrubs that are part of your garden landscape. It is easier to prune when leaves are not present on the shrub, and the plant is more likely to tolerate it before its energy is directed to leaf and bud growth. Many people are often hesitant to prune for fear of cutting flowering shoots at the wrong time, so they simply don’t prune at all. But by mid-summer an overgrown shrub can quickly become a nuisance when it blocks sunlight for perennials and annuals.
There are some rules of thumb to follow when pruning flower bearing shrubs. A plant needs three months of growing time from the time it is pruned until it flowers. Forsythia is one of the first early blooming shrubs. Pruning should take place shortly after it is done blooming which will then allow it to grow in the summer months and set buds for the following spring. On the other hand a Rose-of-Sharon, or hibiscus, should be pruned in early spring to allow for three growing months before it blooms in August. I always adhere to this rule when pruning my larger flowering shrubs.
Pruning is done by thinning, heading back, or rejuvenating. Rejuvenating is more aggressive pruning and should be done on shrubs that put out extensive growth each year. For example, spireas that bloom on new wood each year can be pruned right to ground level. I usually do this in late March. The plants will recover quickly and grow back more densely with better flowering. Some shrubs are best pruned by heading back. This is a method where the tips of the branches are pruned back to allow shaping of the shrub. This is easily done on burning bushes as this shrub puts out a good 12 to 15 inches of growth a season. Remember that if a plant blooms on old wood it is best to prune it after it flowers. Pruning can be done before it flowers, but remember you will loose the flowers for the current growing season. Plants that bloom on new wood should be pruned while the plant is still dormant.
Please keep in mind that the Master Gardener program enables gardeners to serve their communities as horticulture educators. Volunteering is an enriching experience. It allows the opportunity to share the love of gardening with fellow gardeners, apply current knowledge and skills, and continue to learn more about gardening and horticulture. Master gardeners do a variety of volunteer educational youth and community service projects as well as answering homeowner horticulture questions. These questions can be directed to the UW Extension Office at 328-9440.
Until next time. . . happy gardening!
UW Extension Master Gardener Volunteer