We have an apricot tree that gets lots of flowers and the fruit grows to about half an inch, then all fall off. This has happened every year for seven years.
I thought grafting another variety onto this tree might be a solution. But none of the nurseries around Sacramento has anyone that can tell me about grafting. The method seems simple enough, but no information about the time of year to do it or how long until I can see if the grafting was successful.
I did the grafting already with some branches from a tree that has been a good producer.
Any ideas about what's happening with this apricot?
Rich Thomas, Sacramento
According to UC Master Gardener Carol Rogala, fruit and flower drop can occur at any time during the season in response to environmental or physiological conditions. A large number of fruitlets may drop shortly after bloom because they were not fertilized.
Sometimes a drop in young fruit often called "June Drop" occurs in April or May. This may be caused by competition between fruit for growth nutrients and can be helped by early thinning of the fruit on the tree. Apricots usually set more fruit than they can successfully carry, so fruit thinning is essential.
Also situations where no fruit crop is produced or where fruit drops prematurely may be the result of many factors, including cool weather or insufficient irrigation that weakens the tree.
Fruit and nut trees require consistent, uniform soil moisture. Stress during early growth or during fruit production will reduce yields and fruit quality and may make trees more susceptible to boring insects or diseases. Moisture should be replaced well before the trees begin to show stress.
Mild frost may produce shoot dieback and young fruit may drop. Trees can be protected from frost injury by covering them with floating row cover or using protective shelters if freezing conditions occur during bloom or early fruit growth.
Several species of caterpillars roll leaves, and University of California research cites leafrollers as a potential pest of apricot trees where the larvae severely scratch and damage young apricots and cause fruit drop.
More complete information on apricot trees can be found on the UC Integrated Pest Management website at this link:http://www.ipm.ucdavis.edu/PMG/GARDEN/FRUIT/apricots.html
As for the second part of your question: To graft or not to graft. Inserting a portion of one tree onto another tree is known as "grafting." There are several methods of grafting; in some methods, a one-year-old stem (scion) with two buds is placed onto a existing tree (stock). In other methods, a single bud is placed into the stock. The grafts become part of the mother tree, but bear the fruit of their origin.
A complete discussion of grafting is found in Environmental Horticulture Note 85, "Bud Grafting," which can be found at http://ucanr.edu/sites/sacmg/Fruit_and_nuts
Master gardeners at the Fair Oaks Horticulture Center can also provide grafting tips. The schedule of events is available at http://ucanr.org/sites/sacmg. The next plant clinic is set for next Saturday from 8:30 to 11:30 a.m.
Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties.
Send questions to Garden Detective, P.O. Box 15779, Sacramento, CA 95852. Send email to firstname.lastname@example.org. Please put "Garden Detective" in the subject field and include your postal address. To contact your UC Extension directly, call:
Sacramento: (916) 875-6913; 9 a.m.-noon and 1-4 p.m. weekdays
Amador: (209) 223-6838; 10 a.m.-noon Monday through Thursday; email ceamador.ucdavis.edu
Butte: (530) 538-7201; 8 a.m.-noon and 1-5 p.m. weekdays
El Dorado: (530) 621-5512; 9 a.m.-noon weekdays
Placer: (530) 889-7388; 9 a.m.-noon on Tuesdays, Wednesday and Thursdays or leave a message and calls will be returned
Nevada: (530) 273-0919; 9 a.m.-noon Tuesdays through Thursday or leave a message
Shasta, Tehama, Trinity: (530) 225-4605
Solano: (707) 784-1322; leave a message and calls will be returned
Sutter, Yuba: (530) 822-7515; 9 a.m.-noon Mondays and Tuesdays and 1-4 p.m. Thursdays
Yolo: (530) 666-8737; 9-11 a.m. Tuesdays and Fridays, or leave a message and calls will be returned