I have a beautiful crape myrtle tree in a prominent spot in my garden. Ever since I planted it about 15 years ago, it has bloomed beautifully.

Regrettably, and for a change, this year all the flower clusters shrank up and died. Virtually all clusters showed this symptom.

I'd appreciate very much having your thoughts about what it might be and how I might better remedy this situation.

– Larry, Sacramento

Your question about poor flower production does not describe a pest that may be present on the tree, or any condition, such as powdery mildew or sticky substances on the tree. That might have given us a clue to the problem, says UC master gardener Carol Hunter.

Generally, crape myrtle (Lagerstroemia indica) needs moderate feeding. It will also benefit from pruning during the dormant season to increase flowering wood next season.

Remove spent flower clusters and prune out small twiggy growth from dwarf forms. On large shrubs and trees, cut back branches between 12 to 18 inches. If the problem recurs this year after bloom, it would be helpful if you could bring a sample to the UC Cooperative Extension Office. The hours are 9 a.m. to noon and 1 to 4 p.m., Monday through Friday.

We live in Sun City Lincoln Hills. When is the right time to prune our Eureka lemon? Last year, it bloomed, then dropped all the tiny fruit that formed and grew a bunch of long branches that suffered freeze burn in January. It's really ugly!

– Karen, Lincoln

Because some of this wild new growth was burned by freezing temperatures, it is important to leave the branches alone and wait until new growth clearly defines the damaged areas, according to UC master gardener Annie Kempees. You may need to wait as long as six months after the freeze occurred before pruning the branches back to living material.

During the first three or four years after planting a citrus tree, fruit production is light. This period is known as the nonbearing years. The roots are becoming established and the framework of the tree is developing for fruit production.

Unlike most fruit and nut trees that lose their leaves and become dormant in the winter, most citrus, including your Eureka lemon tree, are fruiting during the winter and early spring. When trees are young, they will occasionally send out long branches giving the tree a lopsided appearance. If these branches are left on, the tree will continue growing more branches that will give it its characteristic shape in maturity. You may, however, lightly prune overzealous branches and remove any suckers originating from the bud union.

In a normal year, light pruning may be done in mid-spring. You can train your tree to a high branching structure, or encourage lower growth by leaving the low-hanging "skirt" branches on the tree. The foliage will shade the ground and protect the tender bark from sunburn. This skirting helps minimize weed growth. Best of all, the fruit will be easier to reach as the tree matures.

Considerable numbers of very small citrus fruits (less than 1 inch in diameter) may drop from trees in May, June and July. This is a natural phenomenon, a self-regulating thinning process that protects citrus from bearing too large a crop. It is known as "June drop" and should be expected.

Excessive fruit drop, as opposed to June drop, may be due to nitrogen deficiency, excessive nitrogen fertilization, lack of water, sudden high temperatures, heavy pruning, infestations of mites or thrips, or the occurrence of Santa Ana wind conditions.

GARDEN QUESTIONS?

Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties. Send questions to Garden Detective, Home &Garden, P.O. Box 15779, Sacramento, CA 95852. Send e-mail to h&g@sacbee.com. 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 Tuesday through Friday; e-mail ceamador.ucdavis.edu.

• El Dorado: (530) 621-5512; 9 a.m.-noon weekdays.

• Placer: (530) 889-7388; 9 a.m.-noon on Tuesdays, Wednesdays and Thursdays or leave a message and calls will be returned.

• Nevada: (530) 273-0919; 9 a.m.-noon Tuesday 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.