Growing Concerns: Prune prudently for healthy, productive trees and shrubs
July 3, 2008 · Updated 8:14 PM
Have you noticed that prunes those wrinkly, sticky, black lumps that grandma recommended for regularity are no longer called prunes? That word apparently has the same negative connotation as castor oil, and is not politically correct. The new marketing euphemism is dried plums.
This has absolutely nothing to do with the subject at hand, unless, of course, you have a plum tree that needs pruning. But be it plum or pine, rhodie or rose bush, nows the time for gardeners to sharpen their loppers and contemplate cutting back those overgrown branches.
Entire books have been written on the subject of pruning, and we cant possibly cover everything in this column. But we will discuss the basics, and let you know where to find more detailed information.
The four main reasons for pruning are to train a plant, to maintain plant health, to increase and improve the quality of flowers, fruit, foliage or stems, and to restrict growth.
This is the time of year to plant new trees, and pruning should start during the trees first growing season. Young trees are pruned to develop strength, shape and balance. In the old days, gardeners were told to prune a full third of the new trees top growth. Recent research shows, however, that excessive pruning of newly transplanted trees reduces plant size and hinders, rather than helps, the youngsters. Trees with a central leader probably need little or no pruning, except to shorten branches that compete with it. Then shorten wayward branches to maintain shape and balance, and thats all you really need to do.
Memorize the 3ds: Remove dead, damaged and diseased growth. A damaged or diseased branch or stub is an open door for insects or fungi that can spread to other parts of the tree or shrub. When removing infected wood, be sure to cut into healthy wood beyond the infected portion. Sterilize your pruners with a mild bleach solution or alcohol after each and every cut.
Keeping shrubs and trees from growing too densely promotes light penetration and air circulation, which discourages disease and promotes healthy, even growth. Improving Flowers, Fruit
Youve probably seen those tall, craggy apple trees growing on old homestead properties around the island. I always marvel at the abundance of flowers and subsequent fruit they produce. But most of those apples are pretty puny. Fact is, the more flowers and fruit a plant produces, the smaller they are. Pruning diverts energy into production of larger, although usually fewer, flowers and/or fruit. Correctly done, pruning can also enhance the quality and quantity of foliage.
Why on earth did the people who owned the house before you plant that humungous English laurel in front of the dining room window? Shrubs and trees often outgrow their allotted spaces over time, so think about where you plant before you plant.
If a tree or shrub you love is just too big, pruning is in order. Never, never top a tree, however. It weakens the tree and looks just plain awful!
Basic pruning cuts include removing the 3ds, taking out crossing or rubbing branches, thin, weak and wayward branches, and correcting a Vshaped crotch angle (the angle formed between the trunk and a main limb). The best angle is 45 to 60 degrees.
Take out water sprouts. the long shoots that grow in an undesirable location from the trunk or a major limb. Remove suckers, the shoots that come up from roots.
When to prune
Any time is a good time to remove the 3ds. Prune spring bloomers when flowers have faded. For summer and fall bloomers such as roses, prune before spring growth; a good signal is when forsythia flowers. Prune conifers prior to spring growth, with the exception of pines, which are done just after spring growth. Get to those fruit trees while theyre still dormant (now!). Then you can follow up with their last dormant spray of the season. Unless its a 3d situation, avoid pruning anything in late summer.
For more detailed information on pruning, Washington State University Extension offers several instructional publications for a nominal fee. Call the Extension office in Coupeville (679-7327) to order Pruning Trees (EB1619), or Training and Pruning Your Home Orchard (PNW0400). Sunset and Ortho books offer good pruning guides, as well. An excellent website on pruning (along with photos of some amazing pruning art, go to www.plantamnesty.org.
Mariana Graham writes this bi-weekly column as part of her volunteer efforts as an Island County Master Gardener. Reach her at firstname.lastname@example.org.