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Many southwestern plants grow best when it is really hot

DEAR NEIL: Does it make sense to fertilize in the summer heat?







Lantana blooms

The Lantana New Gold blooms throughout the summer and fall despite the heat. Fertilizing keeps it alive.


Neil Sperry Photo


Dear Reader: That depends on the particular plant species and the vigor of the specimen you’re growing. Many types of southwestern plants do best when it’s really hot. Plants like lantana, Bermuda grass, and sword ferns, to name just three, that many of us have in our gardens thrive in the heat. If we water them adequately, they’ll use up the available nutrients quickly. That doesn’t mean we should over-fertilize them, but it just means that if we notice their growth slowing and the leaf color isn’t as rich a green, it’s probably time to think about fertilizing. Of course, this will be tempered by other factors. Plants that have been recently planted or transplanted may need time to adjust. Water restrictions may mean we don’t want to encourage vigorous new growth right now. Common sense must prevail.

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DEAR NEIL: A friend hasn’t had much success with her peppers, tomatoes, or beans. She recently sent me this photo of the roots of her beans and my first thought was “nematodes.” If not, then what are they?







Roundworms

These are nodules of nitrogen-fixing bacteria, an advantage of plants from the legume family.


Reader photo


Dear Reader: They look like the nodules of nitrogen-fixing bacteria. That’s the many benefits of plants in the legume family. They can convert nitrogen from the air (in the air spaces of the soil) into nutrients that plants can use. When they die and decompose, they release the nutrients and enrich the soil. I’m much more concerned about the mound of what looks like sedge that your friend placed the plant sample on for the photo. It’s huge.

DEAR NEIL: I own a property in rural Oklahoma. It is covered in bois d’arc and black locust trees. I would like to plant some mesquite trees, but no one is selling them. Do you have any suggestions?

Dear Reader: Check with the Native Plant Societies of Texas and Oklahoma to see if they have a source. You can also do it the old-fashioned way: collect seeds in the fall and sow them in moist pits where they can spread. It will take a while for them to reach some size, but you wouldn’t get very large plants in containers either.

DEAR NEIL: I believe a faulty sprinkler system is responsible for my yard having a lot of bare or thin spots in the Bermuda grass. I have repaired the sprinklers and filled in the trenches. Should I seed? I don’t think I can plow as the sprinkler heads would be in the way.

Dear Reader: You will need to till the soil before sowing seeds or laying sod. Buy wire flags from the hardware store and mark the spots where the heads are. You only need to till 5cm deep, avoid the areas directly around the heads. Hopefully your pipes will be significantly deeper. Use an upside down garden rake to smooth the tilled soil, then sow the Bermuda seeds at a rate of 1-2kg per 100m2. Water morning and evening for 5 minutes each for two weeks. Once the seedlings have emerged and are growing, you can gradually water daily, then every few days, but increasingly longer.

That said, I’m concerned that your original lawn may have thinned, not because of the drought, but because of the shade. I get hundreds of questions about thin lawns every year, and more than 90 percent of them are ultimately due to excessive shade. Before you go to all that trouble, make sure St. Augustine (from turf) or a shade-tolerant ground cover like mondo grass isn’t a better alternative.

DEAR NEIL: We lost a large oak tree to what a neighbor called “oak wilt.” Now another tree nearby is dying, too. Is there anything we can do to prevent this? The leaves at the top die first.

Dear Reader: You must immediately call a certified arborist who specializes in treating oak wilt. Diagnosing this vascular fungal disease is difficult and cannot be done with just a sentence or two and without a photo (actually, without knowing what species of oak tree it is). You can learn a lot about oak wilt on the website www.texasoakwilt.org.

DEAR NEIL: Something is causing small twig-like branches to fall off my pecan tree. I’m afraid it will eventually stop growing. I don’t see any insects on it. What could fix this?







Branch belt

Pick up damaged pecan branches to keep the local branch bearer population in check.


Reader photo


Dear Reader: This is damage caused by the twig beetles. The adult female beetles lay their eggs on the ends of these branches and then score the branches with their sharp mouthparts. You will notice that the ends look as if they have been cut all the way around with a knife. When the tip dies, it breaks off and falls to the ground. The larvae develop in the fallen branches, hatch, and the process starts again. There is no prevention or cure, but you can reduce the population by picking up the fallen branches and throwing them away.

DEAR NEIL: Our daughter recently moved to the country in East Texas and has three acres that are literally covered in nettles. She has tried many suggestions, all to no avail. What is the best method to get rid of the nettles? They are even growing through my lawn.

Dear Reader: Suggest that she mow her 3 acres frequently and low to prevent the nettles from growing, flowering and setting seed. Spray vigorous new growth as soon as it appears with one of the 2,4-D, MCPA and dicamba combinations designed for broadleaf weeds. Repeat as needed. If she is consistent for a season or maybe even two years, she should be able to eliminate the nettles completely.

Have a question you’d like Neil to answer? Send it to him via mail in this newspaper or email him at [email protected]. Neil is unable to respond to individual questions.