Plant Fruit Trees
Plant Fruit Trees
By Denise Levine, U. C. Master Gardener
Peaches
Bare-root fruit trees and brambles, including raspberries and blackberries, are showing up in your favorite nursery this month. Bare-root plants, sold in the dormant season only, are not potted in soil so their roots are exposed. Pomegranates, persimmons, mulberry trees, currants and table and wine grapes can also go into the garden now.
If you know what kind of fruit you want but don't know the best variety for our area, ask for help at the nursery. The benefit of buying bare-root fruit trees and vines from a reputable local nursery is that they know what varieties have proven successful in the Napa Valley.
To set fruit, most temperate fruit trees need a certain number of hours of winter chill (between 32ºF and 45ºF) to break dormancy and signal the time to blooms. Different fruit trees have different chill requirements. Your local nursery will know if we usually have enough chill to grow what you want.
Figs, for example, need only a few hours of chill to be bountiful, while a pear tree could need between 1200 and 1400 hours of chill. If you are counting, that is at least seven to nine weeks of cold weather.
The University of California Cooperative Extension office and Master Gardener office also have information to help you. Ask them to send you guidelines on the berries, peaches, pears, apples or even blueberries you are interested in growing. While almost everything grows in our Mediterranean climate, some varieties perform better than others.
Plums are easy, and with all of the native plums in the area and around the countryside, you rarely need a pollenizer. On the other hand, many of us have discovered that it is a rare gardener who can grow more cherries than the birds can eat, and only a few more can get an apricot crop. Not that there aren't glorious exceptions, but they are rare.
The problem with the apricots is that they tend to bloom with the first warm flush of spring, and then get cut down in their prime with the next frost. The Master Gardener office suggests planting apricots (for those who dare) in the coldest spot in your yard, where the frost is the last to leave. If you live on a sloped property, often this spot will be the lowest corner.
Most fruit trees need full sun, and even those that can tolerate some shade will usually produce a bigger crop with more light.
When you are finally choosing your fruit trees, you need to know about caliper. Caliper is the diameter measurement taken just above the bud graft of the tree. Too small, and the tree might not be as healthy as it should be. Too large, and the root ball might be too small to support and sustain the tree in its new home.
So what is the magic number? Between 3/8 and 5/8 inch is the size most experienced orchardists prefer. Often trees sold in discount stores or chains will be larger than an experienced gardener will want, and while bigger may look better, there is a reason they are for sale at the discount store.
While you are measuring the caliper, check to make sure that the graft is well healed. Then brush the sawdust off the roots to make sure they are clean and show no slime or mold.
The University of California recommends a standard rootstock, regardless of the size tree you want. Dwarf rootstocks often produce weak trees, and you can achieve the size tree you want with pruning and training. Standard rootstock also does much better in our typical clay soil. If you want to keep your trees at a dwarf size, you will need to tell your nursery person to make sure the trees you buy have not been debudded.
To get more information on growing fruit trees and growing dwarf-sized trees from standard rootstock, consult the California Backyard Orchard website produced by the University of California (http://homeorchard.ucdavis.edu/general-tree.shtml).