To Prune or Not to Prune

With the coming of winter, we're seeing the end of our fall foliage display. Granted, it's not like New York or New England, where the colors are breathtaking for miles, but I've been pleasantly surprised at all the trees around town that did have some bright fall colors. Now those leaves that were so vivid are beginning to drop. In fact, quite a few trees are completely bare. It's a bit sad to see naked trees, but this is the best time to look closely at the woody branches of trees, shrubs and roses.

Even though we've been grooming our landscapes since human kind first started putting plants in the ground for a purpose, like growing our food, pruning is still something controversial. There're those who love topiary and bonsai, for instance. Individual taste can be, and often is, the determining factor in deciding what plant parts to remove.

However, what we've learned to like might not be in the best interests of the plant. Remember leaves are the food factories within a plant. They produce the sugars that're essential for life, and don't forget - that same set of reactions produces all the breathable oxygen on our planet.

So how do we improve on that? Not an improvement at all - One of the most unfortunate practices we still see, something I believe we should eliminate right away, is the misguided habit of shaving shrubs into balls and squares. The result is a thin layer of live growth at the tips of the branches. This appears “tidier” to some people, but what happens to the plant is the loss of many flower buds and part of its root producing capacity. Look beyond the shell of green or flowers, and the branches are virtually bare, dead wood.

Support comes from

Shrubs aren't the only plants forced to suffer gardeners' insults - too often, beautiful ornamental grasses get sheared into what look like little bales of straw. Now, if someone wants a bale of hay or straw in their front yard, wouldn't it be simpler to go down and buy one at the nearest feed store? Perhaps they're worried that cutting the ornamental grass too low would somehow prevent it from growing come spring. No fear -like the grass in a lawn, ornamental grass develops from growing points beneath the ground. That's why it's possible to mow turf grass to a short height, and it still returns.

The worst thing might be pruning desert natives. Occasionally, an agave will outgrow its space - say, when it was installed too close to a sidewalk - and someone hacks its leaves back. What's left behind is dreadful. The plant's not able to replace those leaves, and the resulting agave or yucca is lopsided and unsightly.

With any plant that needs to fit into a limited space, plan for its size at maturity.

All of this isn't to say that nothing should receive pruning. Plants can respond well, as long as the pruning doesn't turn into plant abuse.

For the health of the plant, don't hesitate to prune branches that are dead, diseased or broken. You can do that any time of year. When two limbs are rubbing against each other, one of them should come out; otherwise, that rubbing can open a wound, which becomes an avenue for plant diseases.

We grow plants for many reasons; aesthetics, of course, but also shade, fruit, privacy, even ground cover. Each of these has different pruning requirements. Generally, we prune a shade tree to maintain its shape and to remove badly growing branches, while a fruit tree's pruned to increase yield.

Look closely at the leafless tree, or the shrub, to get a mental image of the shape and use that as a guide before taking out the pruners.

The internet has so much information on how to groom landscape plants. Unfortunately, not all the information is correct. Call the Master Gardener Help line at (702) 257-5555 for the best plant information, and to find out when I'll be holding my next pruning class.

- Dr. Angela O'Callaghan of the University of Nevada Cooperative Extension.

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