Experts tackle readers’ garden questions.
Q: I planted an apricot tree in our back yard about seven years ago. There were lots of blossoms the first year, but few apricots. From the second year and on, the number of blossoms decreased annually and the apricots also decreased dramatically. This year is the worst year and I do not expect to get even one apricot. I water, fertilize and spray the tree regularly and by the book. In the last two years, I did not prune the last year’s growth. The results are still the same; no fruit. Could you help?
Jamal Zeid, Lincoln
Sacramento County Master Gardener Cathryn Rakich: Apricots, a Mediterranean crop requiring a warm, dry growing season, are grown throughout the Central Valley. In fact, California produces more than 95 percent of the nation’s commercially grown apricots.
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However, the early blooming apricot tree also can make a welcome addition to the home garden. Apricots produce pink or white flowers in early spring – February into March – followed by blushing orange fruit in May. Most apricot trees begin to produce fruit the second or third year after planting, but substantial bearing does not start until the fourth or fifth year.
One of the most common reasons that trees fail to bear fruit is lack of pollination; they may have abundant blooms but never produce fruit. Most apricot trees are self-fruiting, also called self-pollinating, which means they do not require more than one tree for pollination. However, some varieties set better with a little help from cross pollination of a second apricot tree, especially in years with wet, cool weather during bloom.
Other potential reasons for why a 7-year-old apricot tree is not producing fruit include inadequate chilling hours, late frost, alternate bearing, improper irrigation, nutrient deficiency, incorrect pruning and pests or disease.
Most fruit trees, including apricots, need a substantial amount of cold winter weather to end their dormancy and promote spring growth. They require cold temperatures, referred to as chilling hours (approximately 600 to 900 hours below 45 degrees), for normal flowering and good fruit set. After a mild winter, flowering and spring growth can be delayed and irregular, resulting in reduced fruit set. At the other extreme, a late frost also can be deadly to apricot blossoms, ensuring in little or no fruit.
Alternate bearing, which is relatively common in apricots, is when the tree bears heavy fruit one year and a sparse crop the next. If the tree has an especially heavy crop one year, it will use most of its energy to produce that year’s fruit rather than to form flower buds for the following year’s crop. Thinning the fruit early, especially if it’s a heavy crop, encourages the tree to form more flower buds for next year.
In addition, apricot trees need consistent irrigation throughout the growing season. Excessive or insufficient watering can reduce fruit set and quality. Lack of moisture in early summer can result in small fruit; later in the season it can interfere with bud set for next year’s crop. Apricot trees should be drip or sprinkler irrigated every two to three weeks in spring and summer.
Another reason for poor fruit set is nutrient deficiency, particularly nitrogen. However, too much nitrogen can lead to fewer fruit and susceptibility to pests and disease. Therefore, the total nitrogen requirement for the year can be divided into two or three smaller quantities applied over the growing season. Other deficiencies include zinc, potassium and iron.
Inadequate pruning is another thing to consider. Apricots have single, simple buds that can be born on either 1-year-old shoots or older spurs. Spurs are productive for three to five years. Apricots should be pruned moderately each year to encourage new growth on which new spurs can develop. Prune in July or August to avoid introducing fungal disease.
Finally, apricot fruit set can be diminished due to a variety of pests and disease. During the winter dormant season, trees can be sprayed to control San Jose scale, aphid eggs, mite eggs and peach twig borer. Never use sulfur on apricots. In the spring, spray to control brown rot disease and shot hole fungus as soon as blooms start to open. For seasonal steps on caring for apricot trees, visit the University of California website at homeorchard.ucanr.edu.
For more information on fruit tree pests, disease, thinning and fertilizing, visit the Master Gardeners of Sacramento County website at sacmg.ucanr.edu.
Cathryn Rakich is a UC Cooperative Extension Master Gardener for Sacramento County.
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