Maintenance pruning not a fun job, but an important one
Most people associate pruning with winter dormancy. While this is certainly true for the removal of large quantities of foliage from trees and shrubs, maintenance pruning can be conducted any time of the year. What is maintenance pruning? As my colleague Linn Mills says, “It is comparable to housekeeping. It may not be the most glamorous job in the world, but it has to be done.” These are tasks that basically make life easier for those who live around trees and have no long-term effect on the tree. Let’s look at a few examples.
Crown lifting
The tree canopy is also called the crown. Arborists refer to the process of removing lower limbs as lifting the crown. Call it what you want, the removal of the branches near the ground can be done anytime of the year. This makes chores like mowing the lawn, child play and catching some rays much easier. Bear in mind that not all trees with branches near ground level require pruning. It is only for the convenience of the user. In my opinion, there is nothing prettier than a pine or a desert tree with a skirt of bottom branches flirting with the soil.
Removal of dead, diseased branches
This part of maintenance pruning is really a safety issue. We want those below the tree canopy to be safe, so we should be watchful of limbs, branches and even palm fronds that are dangling above. In the industry, these are often referred to as hangers.
Removal of crossing or rubbing branches
Why wait until you do your heavy pruning to remove a small limb that rubs on another. If you see definite scarring on a branch due to rubbing, then remove the weakest or the least desirable branch.
Removal of water sprouts or suckers
These pesky little shoots can rob a lot of energy from a tree, especially on fruit trees. Suckers are those shoots that arise from the base of the plant, often below the point of the graft union. Most fruit trees, and the majority of cultivated shade trees, are grafted. This is done to maintain a good quality clone of a desirable tree, but with a vigorous root stock. Shoots arising below the graft union rob water and nutrients from the desirable portion of the tree. They should be removed as soon as they are large enough to handle. In most cases, pulling the sucker from the base will result in a permanent elimination of the shoot. If you cut them off there is a good chance of reoccurrence. Water sprouts are shoots that arise from aerial branches. They often occur on trees like mulberries and ash. They typically are strongly vertically oriented, and grow fast. The removal of water sprouts will aid in keeping the tree appearing uniform and normal.
Thinning
Certain desert trees like to be pruned or thinned during the summer, including African sumac, mesquite and palo verde. Be careful not to open up the canopy so much that you expose the inner branches to intense sunlight that might lead to sunscald. Remove heavy branches by cutting the ends back as far as necessary to reduce the weight on the branch. Cut at a point where a remaining shoot can take the lead role. This is sometimes called subordination pruning. It is great for balancing the top growth with what is often a much smaller root system. Thinning will help to reduce the wind sail effect of the crown, and to slow top growth. Hold off on thinning conventional shade trees like ash, mulberry and elm until dormancy.
Dennis Swartzell is the marketing director for Mountain States Wholesale Nursery. As an ISA board-certified master arborist and a member of the American Society of Consulting Arborists, Swartzell has been helping Southern Nevadans with their gardening questions for 25 years. If you have a question about a particular plant, or a general gardening issue, send them to Swartzell at treemender@cox.net.