Fruit Tree Care

Master Gardener Denny Pederson was invited to give the Food Gardening Specialists (FGS) an overview of planting, pruning and maintaining fruit trees. While fruit tree care was part of the master gardener intern curriculum, we all learned or re-learned something from Denny’s presentation.

With apologies to Denny if the information is not as complete as his presentation, here are some of the “nuggets” we took away from his presentation:

• Pruning 1) controls the size and shape of the tree (an important consideration given the need to reach limbs and fruit to maintain the tree); 2) opens the tree up for more light and air (important considerations from a pest management standpoint and fruit ripening); and 3) improves fruit quality (after all, that’s why we grow a fruit tree!).
• Most people think they can buy a fruit tree grafted to a dwarf or semi-dwarf rootstock and it will limit the tree’s size. Of course it does—but not to the same degree that pruning does. More than rootstock, variety, water or fertilizer, pruning is the best way to control size. Denny prunes his full-sized fruit trees to stay at six feet tall.
• It is shocking but necessary what you do to a new bare root fruit tree. You cut it off at knee height. This causes lower branching to occur (the second year, the best branches are selected).
• If you have gopher problems, make a planting basket out of chicken wire for your new tree. This basket goes into the hole and extends above ground. Chicken wire will rot in a few years when the tree can withstand varmints. In the meantime, you can use tree-friendly binding to temporarily tie young limbs to the wire so that you can create the ideal 45 degree angle (“crotch”) of the branch relative to the tree trunk. This angle creates a strong branch. A small angle creates a weak branch that can be broken by heavy fruit.
• There are several options for the pruned form of the fruit tree. The two most common are central leader and V- (or vase-) shaped. Consider the fruit crop when deciding how to prune your tree. For example, central leader is good for heavy fruit (e.g., pears, apples, quince, etc.).
• How much of last year’s growth is pruned when the tree is dormant? Grape/kiwi: 80 percent; peach/nectarine/fig: 50 percent; apple/pear/quince/cherry/apricot/plum: 20 percent; citrus/olive: less than 20 percent or not at all (just dead branches, for example).
• Pruning order: 1) dead and diseased wood; 2) crossing or touching branches; 3) water-sprouts and suckers; 4) branches growing straight up and down; and, lastly, 5) according to the type of fruit tree.
• The pruning order sound simple. And, a gardener could stop after step 4 above—but step 5 will result in the best fruit production. Step 5 is not as easy as the other four. Know the tree’s fruit-bearing habits in order not to prune or over-prune important fruit-bearing branches; be careful of the spurs and buds that produce the fruit. For example, quince grows from shoots on this year’s growth while nectarines grow on buds from last year’s wood and apples grow on spurs from 2-5 year old wood.
• What are the most difficult fruit trees to grow? Apricot (blooms too early with frost and pollination issues); cherry (blooms late; prone to disease; bird control needed); and peaches and nectarines (both require heavy pruning and peach leaf curl control; nectarines are affected by fruit-scarring thrips).
• Thin fruit to provide a final spacing of 6-8 inches. This will improve fruit size, reduce biennial bearing, improve color and discourage some pests. This is done when the fruit is small but not too soon (for example, after an apple tree experiences fruit drop).

Denny had much more to teach us including tree selection considerations; thinning cuts versus heading cuts and when each is recommended; how to plant; chilling hours required by different fruit trees and varieties; the pruning strategy for year ones through four; when to prune; sunburn protection; nutrient requirements; pest management; techniques for espalier; and considerations for shaping trees. Denny is a speaker in the SCMG Library Workshop series. He is very knowledgeable about trees as well as dealing with varmints (gophers, deer, voles, etc.). You will appreciate his down-to-earth style and practical advice for the Sonoma County home gardener. Look for his presentations on the SCMG Workshop Calendar. 

Denny highly recommended the UCANR publication, The Home Orchard: Growing Your Own Deciduous Fruit and Nut Trees.  When he is out in the orchard, his pocket (literally!) reference is How to Prune Fruit Trees, by R. Sanford Martin. This thin paperback is currently out of print. But keep an eye out online or in used book stores.