GARDENER'S MAILBAG: What happened to my tomatoes?
Dear Neil: What caused this to happen to my tomatoes?
This is sunscald damage. It happens when fruit is exposed to the intense direct rays of the sunlight, especially after a period of cloudy, cool weather. It can also help happen when the plant loses foliage due to disease. There was a good bit of this after the May and June cloudy spells. Once it turned sunny the vulnerable fruit was exposed. Hopefully you have fall tomatoes planted and growing. This won’t be a factor in fall’s cooler weather.
Dear Neil: I have a very large live oak about 40 inches in diameter. It has a cavity about 12 feet deep and 8 feet long that is about 4 inches wide. I have cleaned it out, but now I’m wondering about filling it with concrete or applying a tar coating. Would you suggest either?
No. What I would recommend is that you have a certified arborist look at the tree. However, filling with concrete is never recommended. It is too permanent. It seals in any decay problem that might be there, and it traps moisture in in a way that keeps it from escaping. Trees normally can heal themselves effectively. The arborist will know what needs to be done. That tree is valuable enough to justify any expense in having the arborist look at it on site.
Dear Neil: What would cause part of a dwarf yaupon holly to die like this? (See photo attached.)
There are several possibilities. This past winter caused that kind of dieback. I even saw it on two or three plants in my landscape. Male dogs can burn the foliage with their bad manners. It’s also possible that that branch was broken by something falling into it or brushing against it. You can prune it out with hand shears and reshape the plant as needed. Apply a high-nitrogen fertilizer to encourage the plant to regrow and fill back in.
Dear Neil: My Monterey oak lost all of its leaves after the February freeze. This spring the leaves came back but now they have all turned brown starting at the bottom. What can I do?
I’ve had a lot of questions on Monterey oaks. Yours is the first, however, where someone asked me about one that went down a second time. I suspect that’s going to happen with a lot of our plant species. Monterey oaks didn’t fare well with this past winter’s cold. I’m hesitant to recommend them for use where they have frozen. It’s one thing to lose a shrub, but it’s much worse to lose big shade trees. They represent too much of an investment of time and space. Replant with something else.
Dear Neil: My 92-year-old mother has a hibiscus with little black specks all over its buds. What are they, and what can be done to prevent them?
Those certainly sound like aphids. They love hibiscus, and they will congregate on the buds and new leaves. Start by trying to wash them off with a hard stream of water. If that doesn’t work, find an insecticide that is labeled to control aphids and that does not have a disclaimer against use on hibiscus. Hibiscus foliage can be damaged by several types of insecticides.
Dear Neil: I have a four-year-old Mexican olive tree that I planted as a memorial for my brother in South Texas. The freeze killed it back, but new branches were sprouting out vigorously. I was gone for a weekend, and when I returned many of the branches were on the ground. The only thing I could find was pillbugs in the holes in the trunk. Would the branches have blown off because of wind, or could the pillbugs have chewed them loose?
It would definitely not have been the pillbugs. Vigorous new branches like that are very brittle and easily broken by the wind. Hopefully your tree will put new growth out yet this season.
Dear Neil: A couple of years ago I noted the death of part of my vinca (periwinkle) crop. You suggested the use of the variety Cora. That did help for one season, but then the problem returned. What advice can you offer?
The disease you’re referring to is Phytophthora, a water mold fungus that really attacks the various periwinkles. The Cora series was introduced as being resistant to the disease, but after a few years it began to affect Coras as well, just as you noted. In recent years growers have introduced Cora XDR vincas, with the “XDR” standing for “extra disease resistance.” So far they seem to be holding up very well. As always, however, plant periwinkles late (no earlier than mid- or late May and through June, even into July. Use fresh potting soil if planting into containers, and be sure beds drain perfectly.
Dear Neil: This is a 14-year-old oak tree that suddenly split and has been leaking a brown fluid. The leaking has since stopped. The tree still appears to be healthy with a good canopy. Any suggestions?
This is radial shake brought on by the extreme cold of February. The fact that the canopy looks good tells us that the tree is probably healing itself. It would not be a bad idea to have a certified arborist check things out. It appears that the tree’s root flare is too low. The arborist may suggest use of an air spade to get rid of some of the soil that has accumulated around it.
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