Q: What can I do with all the leaves in my yard? I don’t want to bag them up, I would like to just run the lawn mower over them and mulch them on the lawn but my husband thinks that it may cause a thatch problem and the lawn may suffer if I do that. What do you recommend?
A: According to a recent study at Michigan State University, you no longer have to bag your leaves. Run over them with a mulching lawn mower until the pieces are about dime size. About 1/2 inch of the grass should show through. Over the winter the leaves will decompose and add nutrients to your soil. Adding a little nitrogen fertilizer will help the leaves decompose more quickly. Most leaves break down very easily with the exception of live oak and magnolia leaves. If you do choose to bag the leaves, find a friend or Master Gardener who will compost them. Most Master Gardeners consider leaves as free fertilizer.
Getting Rid of Grub Worms
Q: When we were dethatching our lawn and pulling weeds from the beds we found lots of grub worms, what can we do to get rid of them and when?
A: The best time to kill grubs in Texas is from March to August. Look for a product containing IMIDACLOPRID, an insecticide that should not harm beneficial insects in the soil. Read the label carefully. The insecticide attaches to the roots of the grass and shuts down the grubs ability to feed. The ability to kill the grubs depends on how deep they are in the soil, how much it is watered in and the amount of clay in the soil. As with the any product it will not wipe out every single grub. In the average lawn there will be grubs at any time of the year, if you find 3 or more in a 12 inch by 12 inch area that it is considered an infestation and a serious threat to the lawn. Most lawn insecticides should not be used within 3 to 4 feet of vegetable crops.
Yellow Dwarf Yaupons
Q: We have 30 dwarf yaupons in our front and back gardens and 7 of them have turned yellow. They have been in the ground for about 10 years and the roots may be affected by our caliche limestone based soil. What treatments can be done and when?
A: First let me warn you that even with treatment, the hollies may never completely green up. Once the roots begin growing into the limestone it is very difficult to get enough product into the soil to do any good. It can be like trying to dilute the salty water of the sea with a few buckets of fresh water. My recommendation is to use a good slow acting high nitrogen based fertilizer at least twice a year and supplement with a granulated Iron product. A Chelated Iron product that can be mixed with water and sprayed on the plants periodically may help to green them up some, but most likely they will remain partially yellow or will gradually go back to yellow over time and the treatments will need to be repeated. This can be a few weeks to a few months or longer. Iron products will stain cement, concrete, brick, tile, light colored stone and terracotta very easily and most times permanently.
Oak tree turning brown
Q: We planted an oak tree several years ago and now it is turning brown what is wrong, it should have grown enough deep roots by now to be alright what can we do for it?
A: It can take a tree any where from 3 to 5 years or more to grown enough roots to be self supporting and thats in a good year. Depending on the soil where you are and how big the tree was when you planted it and any number of other possibilities. It is still my recommendation to water more. Your problems are most likely due to being dry. Do not depend on automatic sprinklers or standing by the tree and watering by hand. You need a dedicated bubbler hear on your irrigation system to water trees or use a stationary sprinkler to water slowly. Unless the water stands around the tree for days after you water or the ground becomes soggy and stays that way for days after you water then you are not over watering. Water at least twice a week or more if you have thin soil or lots of rock in your area.
Drooping pear trees
Q: My pear trees are drooping and looking bad I am watering but they are not getting any better, is something else wrong?
A: It can be one or more things wrong at the same time. Fruit trees and non fruiting pear trees are still fruit trees and can suffer from a root diseases called Cotton Root Rot and when the tree becomes stressed by things such as heat or drought they can die and no amount of watering will save them. All I can recommend is to continue watering and water slowly for long periods of time, do not stand and hold a hose by the tree and think that you will be putting enough water on it. Get a stationary sprinkler or a soaker hose so you can slowly soak the area for 30 to 45 minutes at least. If this maintains the green leaves on the tree then it is not the root disease but stress from heat and lack of water.
Shreaded bark on live oak trees
Q: I was trimming the sucker growth off my live oak trees the other day and a lot of them, not all, but a large number look like something is shredding the bark on the stem, not eating it or taking it off, but shredding it like tiny cat scratching. What is causing it, is it bad for the tree and if so what can I do?
A: What you have is Cicada damage. The damage it self is not bad for the tree, most of it is always on the small twigs and can make the tree look bad but does little harm. Fortunately this most often is in the heat of summer and not in spring, other wise it could open the tree up to oak wilt or decline. But the insect that spread the disease are not active in extreme heat. The cicada roughs up the bark while laying its eggs that hatch into a small larvae that then drops to the ground and burrows in to feed on roots and other plant parts but will do little more to damage the tree. Spraying is not practical as the adults fly around from area to area and most trees are too large to treat effectively. If you must have something done, there are some tree drenches available retail that the average home owner can use or contact a certified arborist for more detailed information and options.