GARDENER'S MAILBAG: What at the brown circles in my JaMur zoysia?

By Neil Sperry
Special to the Herald Democrat
Jamur Zoysia Large Patch Brown Patch

Dear Neil: This is JaMur zoysia planted in my yard in 2006. It’s almost one-half acre in size and it has done well. I fertilized it two weeks ago with 5-20-15. Most of the yard did well with the feeding, but one section started this discoloring in brown circles. It has progressed very rapidly. What is it, and how can I stop it?

This is large patch, also called brown patch. You may recognize it from St. Augustine lawns, but it’s a problem in zoysias as well. It attacks the leaf blades at the bases of their sheaths. They will pull loose very easily. And, as you observed, it starts in circles, and until they grow together, the circles are very noticeable. It can do damage to zoysia, so you would want to apply the fungicide Azoxystrobin to slow its spread. Hopefully the grass will green back up soon. The fungus is more active in cool, wet weather, and we certainly had plenty of both in May. And, by the way, as to your choice of fertilizer… Was that based on a soil test from the Texas A&M Soil Testing Laboratory at College Station? It’s ultimately rare to see them calling for that little nitrogen and that much phosphorus. We are almost always told to avoid phosphorus (middle number) and apply a high-nitrogen (first number) product with much of the nitrogen in slow-release form. You might want to double check your test results.

Dear Neil: I have attached a photo of an unknown fern that was hurt by the cold. First, what type of fern is it? Also, you can see that half of the plant seems to have died while the other half came back from the cold in good shape. Can I safely trim off the dead half without harming the rest of the plant?

6 07 21 Sago Palm Save Half

This is a sago palm, not a true palm, but a look-alike, also known as a Cycad. These had been planted in the ground across much of Texas going into this past winter. Truth be known, they were planted way too far north. Many were lost in the cold and, if people are wise, will not be replanted in the same areas. Yes, you can carefully remove the dead portion without fearing damage to the live half of your plant. However, I might suggest waiting another month or two. Sagos grow best in warm weather, so we are just now getting into their prime time. You never know what other buds might pop out.

Dear Neil: My St. Augustine lawn is being overrun by clover. It started last year. I have tried several 2,4-D weedkillers, but they have not worked. Is there anything else I can do?

Let’s fine-tune what you have already done. We’ll start by trying to identify the weed precisely. Does it have small yellow, bell-shaped flowers, and does it produce upright stems several inches tall? If so, you probably have oxalis. Many people mistake it for clover. That normally wouldn’t matter, except that oxalis is more difficult to eliminate. I would still use the 2,4-D weedkiller spray, but I would put one drop of liquid dishwashing detergent per gallon of spray into the tank before you pump. Set your spray nozzle to a fairly fine droplet size so that you can coat the leaves with the herbicide. You put the detergent in to hold the spray on the waxy leaves. Do not mow for several days before or after you spray, and do not irrigate for 24 hours after spraying. Then be patient. These are some of the more difficult weeds to control. It may take a couple of weeks to see results.

Dear Neil: We have three Monterey oaks on property in Blanco County. The tallest is about 35 feet tall. When the February cold hit, they had just lost their leaves and were just putting out new growth. Since the cold, none of them has had any growth – no leaves at all. Is there any way we can save these trees?

Monterrey Oak Frozen

I have been reluctant to recommend Monterey oaks since I lost one that I planted almost 40 years ago. It was only five years old when it froze, but I learned a hard lesson. I would suggest that you leave the three trees in place through the summer in the hopes that they will send out new growth like live oaks and many of our red oaks are doing. But, sadly, I would not hold out much hope. They are beautiful trees, but we are now discovering why their native range is far south of where we are planting them.

Dear Neil: This is a Tycoon tomato. Are you able to tell from the photo what is happening to its blossoms? You can see the several different stages of loss. We are not getting any fruit.

Tycoon Tomato Not Setting Fruit

The one thing I do notice in your thumbnail photo is drops of water hanging from every plant part. It’s obvious that you were having wet weather at the time the photo was taken. When tomato flowers abort without setting fruit it is because they have not been pollinated. Tycoon is an outstanding variety and it should have been setting. If you have it growing against a solid surface where the wind is blocked and air movement is minimal, try thumping the flower clusters every couple of days. That will shake the pollen loose within the flowers. That simple practice can make a huge difference in the amount of fruit that is set. (Of course, it’s only going to work in dry weather.)

Have a question you’d like Neil to consider? Mail it to him in care of this newspaper or e-mail him at mailbag@sperrygardens.com. Neil regrets that he cannot reply to questions individually.