Q: We purchased our home 11 years ago and every year since, we have been battling olives dropped by 12 trees that surround our home. Our trees are typically in full bloom the second or third week in May.
Last year, we hardly saw a bloom on our trees well into June. However, we do have neighbors with olive trees and some of theirs did bloom in late spring, later than usual. I also noticed that the amount of blooms on the ground were lighter than in past years.
The 2011 crop was the worst that we have seen since we purchased our home. Our neighbors say that the overabundance of olives was the worst they had seen in the 36 years in their home.
The olives also held onto the trees longer. So we had olives dropping well into May. In fact, a few strays dropped in mid-June.
We did have our trees thinned out last January. Did the pruning some how shock the trees?
I want to know if we hit the "jackpot" and our trees just won't bloom, thus no olives this coming May. Or did olive trees in the Sacramento area just bloom late in 2011, meaning a late crop in 2012?
Pat and Julie Sullivan, Carmichael A: When olive trees are pruned during the rainy season, they can become infected with bacterial gall (Pseudomonas syringae) usually referred to as olive knot disease, according to UC Master Gardener Bill Pierce.
If your trees are infected, there is a possibility that this is the cause of no blooms.
Another possibility for the lack of bloom is the tendency of some trees to have heavy crops one year and light or no crops the next.
Excess pruning could account for the loss of fruiting wood. The intention of this note is not to alarm you but to alert you to the possibility of the disease and allow you to take steps to control it before it spreads.
For the home landscape, a combination of cultural practices and sanitation is necessary. For complete details, visit www.ipm. ucdavis.edu and access Pest Note 74156. A copy can also be obtained by sending a self-addressed, stamped business-size envelope to: PN 74156, UC Cooperative Extension, 4145 Branch Center Road, Sacramento, CA 95827.
Q: We have a magnificent mulberry tree in our backyard, and except for the period that it drops fruit we love it. The fruit, however, is a royal pain.
Every year, we spend many hours trying to keep the nasty, sticky mulberries off the patio, and the lawn gets funky and the mess is hard to keep off shoes and out of the house. Is there a way to stop the tree from fruiting? The male tree drops catkins in the front yard as well.
We were told to buy a spray, and were going to try it, but last spring was either raining or windy, and we don't want to spray a 40-foot tree and take the chance of the spray going on other fruit trees or plants, without knowing what it will do. Help!
Elaine and Jim Hudson, Citrus Heights
A: Florel brand spray is a growth regulator recommended to prevent trees from forming fruit, nuts or seed pods, says UC Master Gardener Bill Pierce. Timing is important in its application in spring while the tree is in bloom and the directions on the product should be followed carefully.
If you have other fruiting trees near the mulberry, keep the spray away from their blossoms to prevent fruit loss.
Spraying a 40-foot tree without power equipment is difficult. You may wish to hire a commercial company.
Another way to prevent fruit set is to blast the blossoms with water. Attach a nozzle that creates a strong stream of water to your hose and wet the blossoms two to three times each day from the time you see the blossoms open until petal fall.
This treatment wets the pollen so that fertilization in the blooms cannot take place. This water method may not eliminate all the fruit, but it will significantly reduce the crop.
Please keep in mind that as the crop is reduced, you will also be eliminating a valuable food source for the local wildlife.
GARDEN QUESTIONS?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 email@example.com. Please put "Garden Detective" in the subject field and include your postal address.