Garden Detective

Garden Detective: Live oak breaks out in bumps

What caused the bumps on these oak leaves? The culprit likely was a mite, says a master gardener, and of little consequence.
What caused the bumps on these oak leaves? The culprit likely was a mite, says a master gardener, and of little consequence.

Q: We recently noticed these bumps on the leaves of the live oak tree in our backyard. The tree was started from an acorn in Menlo Park; we planted the tree in 1995. Can you tell us what is happening and what we can do to treat it? It appears to be only the lower limbs at this time. We would greatly appreciate anything you could tell us. We have not had any luck at the nurseries.

Neysa and Edward McLoughlin, Sacramento

According to UC master gardener June Bleile, it appears the bumps on your live oak leaves are caused by the live oak erineum mite.

The mites cause blisterlike swellings that protrude from the upper leaf surface. On the lower leaf surface, the blister appears as depressions filled with mats of rusty brown hairs. The blisters are usually green but turn brown.

The mites overwinter in the leaf blisters or in leaf buds and establish new colonies on the underside of spring foliage. The damage caused by the erineum mite is generally limited and of little or no consequence to affected trees, and no control is known or needed.

Your oak tree should be fine.

Q: Where can I buy Brandy Boy tomato plants? Do they need lots of sun? When is the best time to plant?

Art Tourtillott, Sacramento

A: Brandy Boy tomato plants as well as seed are available now from Burpee (, its exclusive online source. You may also ask your favorite nursery to order plants for you.

Like most tomatoes, they need a minimum of six hours of sun a day to produce fruit; eight hours or more is ideal. Although Sacramento weather has been unusually warm, wait until April to set out your plants for best results.

Because they need warm soil to really start growing, tomatoes planted too early usually just sit there and grow little if planted in March. Wait and you’ll get better results – and more tomatoes.


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 h& Please put “Garden Detective” in the subject field and include your postal address. To contact UC Extension directly, call:

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