Neil Sperry's Mailbag

DEAR NEIL: You recently addressed a redbud problem, but please go one step farther. Attached is a photo of my redbud's leaves. It's at least 27 years old. I used green sand on a dwarf yaupon at the tree's base. What is causing the leaves to turn brown?

It appears, from your photo, that your tree has suffered some type of environmental scorch. It may have been from a spray that drifted onto its leaves, or even moisture that beaded up on them before the hot sun hit them.

It does not appear to be any type of disease. Watch the tree for a week or two to see if new growth that it produces is free of the problem. If so, then it's something that was transitory in nature. If it persists, look more closely at the trunk for signs of borers, decay or any other reason for the tree not to be carrying water to the leaves properly. In all candor, your tree is probably at, or beyond, the average life expectancy for a redbud.

DEAR NEIL: What type of grass would hold up best to three black labs in our back yard?

Since you didn't mention that shade was any kind of factor, I'm going to assume full sun. Common bermuda would be, by far, the best for that kind of really rough traffic. It's quick and tough, plus it produces underground runners (rhizomes) as well as the stolons on top of the ground, so it has the greatest bounce-back capability.

DEAR NEIL: Under what circumstances would root fertilization be necessary for trees?

Plants take nutrients in through their roots, so "root fertilization" is almost always going to be the way to go. If you're talking about inserting a rod into the ground and then injecting a plant food through it, that would seldom be needed. There are some inherent flaws with that means of fertilizing large trees. First, 90 percent of any tree's roots will be near the soil surface. If you use a long rod, and if you insert it too deeply into the ground, it will miss many of the roots. Also, it tends to concentrate the nutrients into specific areas. Spreading granules across the soil surface, then watering them into the root zone is usually best. The one exception might be if you have a tree on a slope that is steep enough that the water and fertilizer pellets might run off. But, if you do use a rod, don't push it more than 6 or 7 inches into the ground.

DEAR NEIL: I have a large bed of English ivy. Unfortunately, it's full of some kind of disease. The leaves are all turning yellow and spotted black. What can I do? Someone told me to hand-pick the leaves, but it's a huge planting.

That's a fungal leaf spot, and it can be a real problem with English ivy. A general-purpose fungicide should help bring it under control, but you'll have to spray on 10-day intervals until it's eliminated. It always seems worse in the spring when the leaves are fresh and soft.

DEAR NEIL: What would help a Lady Banksia rose bloom more heavily? It used to do so much better than has the last several springs.

Full sun, good soils, frequent watering when it's dry, and regular applications of a quality rose fertilizer should be all that it takes.

Above all, don't prune it during the winter. Many people wonder why their climbing roses don't bloom well, but they're often pruning them in February along with their bush types. Climbers set their buds in the fall and winter. Wait until after the petals have fallen to reshape your plants.

DEAR NEIL: I transplanted a fruitless mulberry tree this past winter. It's a fairly large tree with a trunk 3 inches in diameter. I didn't know I was supposed to prune it after I moved it. Now it's dropped almost all of its leaves. Is it too late to prune it? Will it hurt it to prune it in the summer?

Go ahead and prune it. It may not make it until next year otherwise. You can either cut limbs back, or thin out unneeded limbs, or both. You also need to be really careful to keep it well supplied with water. If the tree merits the expense you should also protect it from invasion of borers by spraying the trunk with a borer preventive every 6 weeks from late spring through early fall. Limit your expenditures, however. Facing the facts, a tree that large has a high probability of dying when it's showing symptoms like you described.

Neil Sperry
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