Seaweed's good, but more is needed for spider mites

Question: What can I use to rid my shrubs of spider mites? The shrubs are covered with light (and unsightly) spider webs. I prefer not to use pesticides.

C.S., Dallas

Answer: Spider-mite infestation is a clear sign that water is not effectively being pulled up by the roots or moving into the plant. The problem can be caused by too much or too little water, chemically imbalanced soil, compacted soil or other environmental issues.

Liquid-seaweed spray is highly effective to rid plants of spider mites. In fact it works as well as or better than chemicals. Most mixtures that contain seaweed also will work.

However, the mites will reinfest unless you correct the problem that invited them in the first place.

Question: I live in Waco and had a certified arborist check out my 20-inch-diameter tree. He said it has borers and wants to inject it with a chemical poison. He said we could do your Tree Trunk Goop after that. Is there any other way we can go instead of chemicals? He said your Sick Tree Treatment would be good after we treat it with this chemical.

A.N., Waco

Answer: Like most professionals, arborists have differing opinions. I believe, for example, that chemical injections will weaken the tree. I would skip the chemicals and use the Sick Tree Treatment.

Borers attack trees that are in stress and weak. Relieve the stress, and the pests go away.

Tree Trunk Goop can be applied right away to the insect holes in the tree.

Question: I have bald cypress trees in my yard. The root nodules are becoming a problem for the lawn mower. Would it damage the trees if I trimmed them off at ground level?

B.D., Dallas

Answer: Yes, removing the knees would harm the tree because they are part of the root system. Convert the area where the knees are growing to mulch or ground cover and try to dry out the soil.

The knees grow in overly moist soil and can even allow bald cypress trees to grow in water.

Question: The tomato plants growing in pots on my patio are forming scabs on the blossom ends that are as large as the bottoms of the tomatoes. If the green part were dark brown, it would look like a buckeye. What causes this?

B.R., Dallas

Answer: That's blossom-end rot, and it is prevented by having calcium available to the plant. Watering properly is part of the solution.

Water thoroughly and allow a drying period between waterings. Apply soft rock phosphate at a rate of about 3 to 4 pounds per 100 square feet of garden area. Spraying the foliage and drenching the soil with compost tea or my Garrett Juice formula also will help.

Question: Can nematodes be put out with a hose-end sprayer?

B.J., Cedar Hill

Answer: Yes, just remove the strainer so clogging won't occur. Use nematodes to control fleas, grub worms, fire ants, termites, thrips and other pests that use the soil for at least one of their life cycles.

Question: What is your recommendation for the nutritional needs of bonsai trees?

D.G., Plano

Answer: Drenching with compost tea or Garrett Juice (monthly at the most) is hard to beat.

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