QUESTION: My gardenia plants were damaged by frost. The damage is visible but not severe. What should I do? I watered the shrubs before the freeze. Should I also cover them before and during a freeze? I grew up in Wichita Falls, where we grew gardenias and had large shrubs with lots of flowers. I want to grow gardenias, but what am I doing wrong? I think these are dwarf varieties, if that makes a difference.J.R., Dallas
ANSWER: Dwarf varieties are more cold-sensitive than large gardenias. Large varieties of gardenias also are easier to grow than dwarf varieties. The damage you described probably is only cosmetic, but spray the plants monthly with liquid seaweed or an organic mixture that contains liquid seaweed. Cover the plants with floating row cover during freezing weather.Avoid using synthetic fertilizers, which create weak cellular growth and increase the risk of freeze damage.
QUESTION: We have a 25-year-old, 30-foot-tall blue spruce that looks sick. Some of the branches have dead sections. What should we do? D.H., Duncanville
ANSWER: The photo you sent to me indicates that the tree is planted too deep. Hire a certified arborist to use an Air-Spade to remove excess soil around the trunk and to expose the root flare. Then, follow my Sick Tree Treatment. Relieving stress on this tree is very important.
QUESTION: I have 50 pounds of lime. Can I use it on my lawn? D.W., Dallas
ANSWER: Why do you want to use lime? Is your soil deficient in calcium? I recommend that you have a soil analysis done by Texas Plant and Soil Lab in Edinburg (www.texasplantandsoillab.com; 956-383-0739) to determine what the soil needs before you apply anything as strong as lime. Lime is not needed or recommended unless the soil lacks available calcium.
QUESTION: I have a dozen native cedars that are infested with bagworms. Is there an organic way to get rid of these pests? S.F., Frisco
ANSWER: There's nothing you can do during winter, but there is when the trees start growing in the spring. Beginning then, spray the trees monthly with a mixture made with 1 gallon of Garrett Juice, 2 ounces of orange oil and 1 teaspoon of Bio-Wash.
QUESTION: Grass won't grow around a large maple in my yard. At first, I thought there might not be enough sunlight and so I pruned the tree's lower branches and those of a nearby crape myrtle. Is it possible that the maple takes so much water that grass can't grow? We don't have automatic sprinklers. We water manually a couple of times a week when the grass is growing. R.M., Allen
ANSWER: Both the tree and the grass need full sun for best performance. Tree roots also compete with grass roots. Guess which plant wins? I recommend that you solve the problem by covering the area near the tree with mulch or by planting a shade-tolerant ground cover. Native horseherb is a good ground cover for your situation.
QUESTION: I have an Arizona ash that is being killed by borers. The tree may already be dead.If we cut the tree and burn the wood in the fireplace, could the borers move to other trees nearby?J.B., Flower Mound
ANSWER: First, the tree is not dying because of borers. It has borers because it is dying. Arizona ash is a low-quality tree and has a short life span even under good conditions. Other issues causing the demise of the tree could include contaminated or compacted soil, herbicides, being planted too deep or having circling and girdling roots. Cutting the tree for firewood is not a problem. Borers will infest other trees only if the trees are sick and weak.
QUESTION: How should I protect geraniums during winter? A.S., Calera, Okla.
ANSWER: Mulch the soil around geraniums and cover them with floating row cover during freezing weather. Even after taking these measures, you may need to replace the geraniums next spring unless this is a mild winter.
QUESTION: What is the best mulch for home gardens? D.M., Richardson
ANSWER: The best mulch for any location is shredded native tree trimmings. Shredded plant material that grew on the same property is even better. Compost is the best mulch to use around small plants. Pine needles also make excellent mulch, but pine bark is not good because it washes and blows away. And when pine bark decays it forms chemicals that inhibit plant growth. Cypress mulch is bad because its harvesting and shipping create environmental problems. Cypress mulch also creates a mat in the garden that blocks air flow, and cypress mulch doesn't break down in the way that a good mulch should.