by Marla Koss, Alameda Backyard Growers Board Member
Alameda Sun, Thursday, April 12, 2018
Unculled peach branch.
As Alameda’s deciduous fruit trees have come out of dormancy, passers-by might be forgiven for having simply enjoyed the beauty of their blossoms, unaware of the dynamic little miracle advancing the tree’s true mission. In super-slow-motion and from the ground up, reproduction takes place in the form of juicy, sugar-laden fruit. With the help of a root system in a new cycle of growth, and the process of winterstored sap being drawn up into every reach of the tree, flower and foliage growth are thus ensured.
Spring arrives cloaked in beauty and hints at a promise of abundance come summer, but for owners of one or more fruit trees, it also exacts a sea of human sweat in return. Culling (hand-thinning) excess fruit from a tree in spring stops a fruit tree from overcommitting itself, breaking branches from a heavy fruit load and setting itself up for alternate (biennial) bearing.
Peaches and nectarines should be thinned to one every 5 to 7 inches along the branch. Remove “doubles” and small, disfigured or damaged fruit as well. Thin apricots and apriums to 3 to 5 inches apart and plums or pluots 4 to 6 inches apart. Apples and pears produce a cluster of flowers and fruit from each bud. Thin to one fruit per cluster; if the overall crop is light, you can leave two per cluster. Retain the largest fruit whenever possible.
During late spring and summer, flower buds begin to form for next year’s flowers. Excess fruit set one spring may cause hormonal signals to produce more foliage and fewer flower buds the following spring. For this reason, fruit thinning is necessary in many species to prevent alternate bearing patterns.
Inspect stone and pome fruit trees for darkened or scorched-looking blossoms, leaves and twigs as well as wilting branch tips. These could be signs of fire blight (Erwinia amylovera) or blossom blast (Pseudomonas syringae), two pathogens that can spread rapidly in wet spring weather. Fire blight is usually most severe on pear trees, but can also infect apple and others, causing major damage or even the death of the tree. Prune out any infected areas as they become apparent and dispose of the diseased material immediately.
Photos by Marla Koss Here, the same branch of a peach tree photographed before (above) and after the culling of excess fruit. The process of culling excess fruit from a tree in spring prevents a fruit tree from overcommitting itself, broken branches from heavy fruit loads and biennial bearing, meaning producing fruit on alternate years.
Spring is the time to begin pruning citrus trees. Remove dead branches and suckers growing from the base of the tree. Suckers are often thorny and have foliage that may look slightly different from the rest. Take out crossing branches and those with large thorns that grow straight up (these will not produce fruit). Do not prune away more than 20 percent foliage in a given year.
Finally, fertilize figs, stone and pome fruit in May. And when June arrives, try to grab that first ripe apricot before a squirrel does!
Read the original article in the Alameda Sun here, or download a PDF of the article.