78°F
weather icon Clear

Sap bubbles on plum trees don’t always mean borers

Question: Last week I noticed sap bubbles 6 to 8 inches off the ground on the trunk of my year-old Santa Rosa plum. I removed the bubbles and reapplied the whitewash. I checked again today, and they are back. I’ve had plums before, and the borers always win. I had hoped the Santa Rosa would do better. What can I do to save this tree?

Bubbles on plum trees don’t necessarily mean borers. They can do this with high temperatures. If you don’t see any other evidence of borers, such as bark coming off especially on the south or west sides, then I would leave it alone. Repainting is fine.

Try to keep as much shade on the trunk as you can from the canopy or even lean a board on that side of the trunk to shade it if you care to. But for now, just get some shade on it.

Bob Morris is a professor emeritus in horticulture with the University of Nevada and can be reached at extremehort@aol.com. Visit his blog at xtremehorticulture.blogspot.com.

Don't miss the big stories. Like us on Facebook.
THE LATEST
Some petunia varieties can stand up to our summer heat

There are lots of different kinds of petunias. For instance, the Madness Summer Series can take the heat, but petunias typically are not known for that.

Watch out for hornworms lurking in your garden

Anyone who has been gardening for a while has a horror story or two about hornworms, which infest many vegetables in the tomato family.

What can be done about high boron levels in soil?

Boron is one of the salts commonly found in desert soils. It can be present naturally or it can accumulate over the years in such places as horse corrals.

Do honeybees prefer pink flowers over white ones?

All of the so-called temperate fruit trees flower in the spring. The white-flowered types such as almonds, plums and pluots, apples and pears usually flower a bit later.

Is redbud tree a good choice for pool area?

My landscaper is recommending a redbud tree in the planter attached to my pool. I asked him if that’s a good tree to plant so close to the pool.

Can scent tell me what kind of plant this is?

You should smell a big difference between bay laurel and cherry laurel, which come from different plant families despite their similar names.