The Coastal Gardener: Time for winter pruning of fruit trees

Last week I tackled one of the most misunderstood home gardening chores: the pruning of stonefruits and other deciduous fruit trees. In that column I explained the purpose of winter pruning is to achieve quality fruit and a higher yield, not to control tree size, which is often attempted. Summer is when these trees should be pruned to restrict size. Cutting back these trees heavily in winter will not reduce the tree size; it only serves to eliminate most fruit production, while forever making a mess of the tree’s branching and structure.

As promised, this week I’ll quickly explain the 1-2-3s of winter stonefruit and deciduous fruit tree pruning. I don’t have space to go into too much depth, but I can at least provide a primer.

The first step for is to completely remove, leaving no stubs, all branches that are crossing through the center of the tree, from one side to the other. Next, completely remove any dead, broken, damaged or diseased branches. These first two steps are universal for any common stonefruit tree.

Now let’s get specific. We’ll start with peaches and nectarines, which are botanically almost identical. These trees produce their fruit directly on the stems that the tree produced last year. Because peaches and nectarines are aggressive growers, they always need a lot of pruning.

Start by completely eliminating about half or more of last year’s growth. Again, cut these stems where they originate, leaving no stubs. When choosing the stems to prune away, your objective is to space the remaining stems through the tree as evenly as possible, so that light and air can penetrate, ripen the fruit and avoid branches that might otherwise break under their fruit load.

In my experience, a healthy tree, peach or nectarine, after pruning, will have its remaining one-year-old stems spaced about every 8 inches. Remember, these are the only parts of the tree that will produce fruit.

Once this is complete, the final job will be to work through all the remaining one-year-old stems and cut them back one-third of their length. This is done because peaches and nectarines produce their fruit on the center third of this growth.

Let’s move to plums, pluots and plumcots. All of these fruit trees produce their crop quite differently than peaches and nectarines. Instead of fruiting directly on the stem, these trees flower and fruit on small stubby growths called spurs. Fruits usually develop on the same spurs several years in succession. So the goal of pruning these trees is to encourage and preserve these fruiting spurs.

On these trees, gardeners sometimes mistake spurs for little dry or dead branches and trim them off the tree, guaranteeing no fruit for a few years.

Begin by pruning out many of the upper middle branches completely, with the goal of opening the center to sunlight and air, much like an upright funnel. Cut back the long whip-like new growth about two-thirds to three-quarters and completely eliminate as many of these as necessary to end up with branches spaced about 1 every foot. Always be mindful to preserve the fruit spurs where possible.

For apricots, which fruit on both spurs and directly on last year growth, follow much of the same strategy as for plums. But, while plums grow very upright, apricots are much more spreading. Remove completely any branches that are nearing the soil, then remove enough of last year’s new growth completely, so as to evenly space the young stems about 8 to 10 inches apart. Unlike plums, pluots, plumcots, peaches, nectarines or even apples, do not shorten the remaining stems, because fruit usually appears near the tips of the stems.

Apples produce fruit only on spurs, each one bearing for several years. As in all fruit trees, begin by thinning the growth to allow an even distribution of branches and stems, being careful to leave no stubs and to preserve the fruit spurs wherever possible. Apples often produce long, straight growths, which can overwhelm the tree and create an awkward growth habit. These growths should be headed back about two-thirds, which will preserve the area where fruit spurs typically develop.

A few wrong cuts can nearly eliminate fruit from your tree. But an understanding of a few basic needs of these trees can greatly increase both the quantity and quality of your harvest. Proper pruning will lead to a healthier tree, good structure and, most importantly, delicious fruit yields for many years.

RON VANDERHOFF is the nursery manager at Roger’s Gardens, Corona del Mar.

There is an invasion of slugs in my many potted plants. I’ve sprinkled Corry’s and Snarol, but that isn’t working. Suggestions, please!

Shirley, Balboa Island

Answer:

Corry’s and Snarol will work. Both are metaldehyde. Although they will work, I’m not a fan of either. Metaldehyde is a synthetic poison that is quite toxic, not only to snails and slugs, but to all warm-blooded mammals as well, including dogs and cats, birds, opossums, children, etc. If you use it, metaldehyde takes a little while to work and isn’t very effective on cool, overcast days, coincidentally when slugs are most active. Basically, when a snail or slug ingests metaldehyde it slowly paralyzes them, but only for several hours. If it’s bright or dry the snail or slug will usually dehydrate and die, but if it is cool or moist it may recover. Alternatively, I suggest iron phosphate (brand name Sluggo). This is a natural and all organic product that causes no harm to the environment or to pets, mammals or people. It is used much the same, but works at any temperature and the slugs will not recover, regardless of moisture or temperature.