Spring Gardening News Distributed 02/22/08
Most spring and early summer flowering shrubs break the usual rule for pruning. Unlike trees, which normally should be pruned in winter, spring bloomers should be pruned after they finish flowering.
If spring bloomers are pruned in the winter, their flowers will end up in the compost pile instead of showcasing the landscape. Hold off pruning azaleas, forsythia, hydrangea and gardenia until they’ve finished flowering, advises LSU AgCenter Northwest Region horticulture agent Denyse Cummins.
Azaleas can bloom from March through April. Some can rebloom in early winter, and newer varieties can produce lightly all year long. That long blooming season can make a pruning schedule even more confusing, but if you prune right after the last flush of flowers fades, you can’t go wrong, according to Cummins.
Try to finish up pruning by the Fourth of July for the traditional varieties. Those plants will begin to make next spring’s flower buds in the fall. Go out and look for the buds, and you can even get an idea of how good the show will be next year.
If you are going to do something drastic, like bringing the height down on a really tall, older bush, start early to give the shrub plenty of cool days to recover from the shock. For extra insurance, cut down only one-third of the bush each year for three years.
Some plants can be temperamental. “Be very cautious pruning native, deciduous azaleas,” Cummins warns, but with a touch of sarcasm, adds, “The plants seem to take pruning as a personal insult and sometimes may even die from the shock just to spite the gardener.”
Gardenias tend to get tall and leggy as they age. Wait until the wonderful perfumed flowers finish in June before cutting them to knee height. They will respond very well, especially if you also toss out a few handfuls of granular fertilizer at the base of the bush after you finish pruning.
If the leaves are pale, dissolve a handful of Epsom salts in water and pour over the root system. Epsom salts is composed of magnesium, which helps green up leaves, and sulfur, which acidifies the soil for these acid-lovers. Water well to dissolve the fertilizer, and then water regularly. You’ll be rewarded with a more compact, bushier, greener flowering shrub for the next bloom season.
Lack of flowering in hydrangeas is a common complaint. “They were gorgeous in my grandma’s yard; what am I doing wrong”? If plants are getting enough water to keep them from wilting during the summer, they are probably lacking flowers because they are being pruned too close to bloom time. The dried flowers remain on the bush so long it’s sometimes hard to tell when blooming is over.
Prune when the blooms stop looking fresh and begin to look papery. Prune out any overly long shoots that ruin the overall shape, but also remove all of the weak, thin shoots from the center.
Thin shoots rarely bloom, and, if they do, they produce small, inferior flowers. Prune them all the way to the ground, leaving only nice fat shoots.
Every flowering bush does not need to be pruned every year. Pruning is often more satisfying to the gardener than beneficial to the plant. Resist making those casual snips, and be proud of the job you’ve already done, Cummins advises.
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On the Internet: LSU AgCenter: www.lsuagcenter.com
Contact: Denyse Cummins (318) 698-0010 or DCummins@agcenter.lsu.edu
Editor: Mark Claesgens (225) 578-2939 or mclaesgens@agcenter.lsu.edu