Q I live in rural Perry County on 15 acres of woods. I have cleared underbrush and thinned some of the larger trees, and it is all very clean and pretty.
I am losing a lot of trees. Most of the sweetgums have died in last six months. A large number of hickories and most of the red oaks and three post oaks also have died. They die and rot very quickly. The bark is pushed off by a brown powdery material, especially on hickory and red oaks. They seem to die in clusters. Could this be caused by fungus or insects? I know stress of drought is part of the cause.
AS evere weather in many forms can affect our trees.
Drought is not something that will kill a tree overnight, but it does take its toll slowly. We had two summers back to back that were awful, but lastyear we had a milder season. This winter has not been kind.
Sweetgums are usually pretty tough trees, but extended drought can do in a lot of plants, or make them more susceptible to problems.
We have been losing quite a few oaks to hypoxylon canker. This disease hits when trees are stressed. By the time the outer bark sloughs off to expose the grayish mycelium underneath, the tree is usually too far gone to be salvageable. When you have large acreage, watering is usually not practical, but do try to keep a good layer of mulch down - that can conserve what moisture we get. Typically, insects and diseases don’t kill across species lines but tend to go after a specific host - at least at first. When we see widespread death across species, it is usually something physical or chemical causing the problem. Could lightning have hit the area? Gradually start planting new trees to replace those you are losing.
QI have a variety of azalea that blooms from spring through fall. It needs pruning. When should that be done? It has gotten sort of leggy, with long stems. AI am guessing you have an Encore or some other reblooming azalea.
While they don’t bloom nonstop spring through fall, they do bloom nicely in spring and fall, with a few scattered blossoms all summer. If they need pruning, the time to do it is in the spring after the first flush of blooms. Fertilize then as well, and the plants should thicken up and give you great blooms again in the fall.
QI live in Bella Vista, and last year my coreopsis plant had black worm-like bugs all over it, eating holes in leaves and eventually killing the stalk. I sprayed them but had to cut the plant down to about 4 inches in September. Do you know what these bugs are and what can I do to prevent them this year?
AI don’t know of a worm-like bug, but there is a small black leaf-eating beetle that has become a pest of coreopsis in the past couple of years.
Coreopsis leaf beetle is the common name, and Phaedon desotonis is the Latin name. It has been seen in Arkansas and also in Alabama, Florida and Texas.
Heavy populations can eat the coreopsis to the ground, but it usually hits in the late spring or early summer, not September. Monitor your plants, and if you spot the pests again, use one of the insecticides that can control them. But early detection is always important.
Q I am hoping that you can give me some insight on my rose problem. I have two double Knockout bushes, and one of them developed a problem last year. It started getting brown spots on the leaves and then the leaves fell off. The other plant did fine.
Right now one has some dead leaves, and the other is pretty sparse. What should I do to start the season off right?
A While the Knockout roses are more trouble-free than most roses, we have been seeing some cercospera leaf spot in recent years. The original, single-flower-form red rose seems to be the most resistant to problems, while the double form and the yellow roses in particular seem to be a bit harder hit.
Our pruning recommendations have changed in recent years. In the past, we told you to prune minimally - up to one-third of the plant.
Now the recommendation is to prune all Knockouts down to about 18 inches from the ground. Don’t just come in and do a straight cut, but selectively thin the plants. This can help open the plant up and get better air flow. Let’s hope it will cut down on your leaf spot.
This pruning also takes the old tops out and should help to keep the rose rosette virus down, since any of the mites that could be overwintering in the plants will be removed. Do clean up the debris around the plants as well, raking and removing fallen leaves. Wait for late February to get this done and when the plants have fully leafed out, give them a shot of fertilizer. Good sanitation and proper pruning can help, but monitor the plants this season, and if you see the leaf spot returning, you may opt to spray with a fungicide.
Janet Carson is a horticulture specialist for the University of Arkansas Cooperative Extension Service. Write to her at 2301 S. University Ave., Little Rock, Ark. 72204, or email her at
HomeStyle, Pages 35 on 02/15/2014