I have a crape myrtle tree that was planted in my backyard about four years ago in April. That first year, it got some blooms and also some fungi.

I sprayed it with some anti-fungal stuff and that seemed to help. But the next year, it only got a few blooms and none the following year. My gardener transplanted it to a spot where he said it would get more blooms, but again this year nothing at all. I have a drip system and the leaves seem healthy enough. Any suggestions?

– Sheila Bruton, Sacramento

According to UC master gardener Carol Rogala, crape myrtle trees can grow in all climatic zones; they do best in full sun.

They should be watered deeply but infrequently. To encourage the next season's bloom, prune during the dormant season – December through early March. These trees are hardy to frost and generally thrive in Sacramento.

First question to you would be: How much do you water? Crape myrtles need well-drained areas to grow well. It may be getting too much water depending on where you have it planted, especially if it's surrounded by lawn. Keep weeds and lawn away from the trunk.

How much new growth did your crape myrtle have this spring? Crape myrtles need to have new growth each spring to produce summer flowers. They require at least six to eight hours of direct sun daily to bloom well.

Some varieties don't flower as vigorously as others and heavy infestations of aphids decrease flowering. Drastic pruning or pruning after new spring growth can delay summer flowering. Excessive fertilization – especially high amounts of nitrogen – in conjunction with other factors, primarily improper pruning, can eliminate or delay flowering.

If you suspect a fungus such as mildew: Apply protectant fungicides to susceptible plants before or in the earliest stages of disease development.

Once mildew growth is mild to moderate, it is generally too late for effective control with protectant fungicides. These are effective only on contact, so applications must thoroughly cover all susceptible plant parts.

As plants grow and produce new tissue, additional applications may be necessary at seven- to 10-day intervals as long as conditions favor disease growth.

Protectant fungicides are applied before disease appears, usually when the tree is still dormant. Use eradicants at the earliest signs of the disease.

If you continue to have a problem, you may want to consider removing the tree and replanting with a variety that is mildew-resistant. They are available in a variety of colors.

GARDEN QUESTIONS?

Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties.

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