Dear friends: Every week, when I open your questions to see what’s troubling your horticultural minds, I find 10 or 15 new questions about dead or bald spots in lawns. Just for the record, I’ve addressed each of them here already this summer, most of them a couple of times, and I want to keep my column at least a little bit “newsy.” I didn’t want you to think that I’m ignoring you.
Let me do a quick summary, then I’m not going to revisit these topics again for 2020.
• St. Augustine that is yellowed in irregular, large areas has probably been hit by gray leaf spot. You should be able to see the diamond-shaped lesions on the blades and sometimes on the runners. Azoxystrobin (sold only at consumer level as Scotts Disease-EX) will control it.
• St. Augustine that appears dry but isne’t helped by irrigation is probably being attacked by chinch bugs. They will appear in the hottest, sunniest parts of the yard. To see them you’ll have to get down on your hands and knees and part the grass at the edge of the dying grass. There are several insecticides labeled to stop them. Don’t delay.
• Any grass that is dying in areas that receive less than 5 or 6 hours of direct sunlight daily may very well be failing due to insufficient light. St. Augustine requires 5 or 6 hours; bermuda 6 to 8; and zoysias 6 or 7. You’re wasting your money to keep planting sod thinking that new grass will make any difference.
• I’m seeing bermudagrass problems this year at levels that I’ve never encountered before. If you’re seeing areas that suddenly turn brown in really odd patterns, do the research on Pythium blight. Texas A&M plant pathology has a really good write-up on it online.
• Bermudagrass mites cause the grass to be stunted and the runners to be extremely clubby. I’ve seen more of this this year than in my prior 49 years of helping Texas gardeners. Clemson University has really good photos and information on dealing with this microscopic pest online.
And now, the next really critical topic in lawn care…
Do you remember all those unsightly weeds you had in your lawn about the time this COVID-19 thing forced us to stay closer to home back in March? We were seeing annual bluegrass, rescuegrass and ryegrass on the grassy-weed side, and we still had henbit, chickweed, dandelions and clover blooming their ugly heads off after the winter.
Well, gardener, the time to control those has arrived again. You have between now and Labor Day to apply pre-emergent weedkiller granules. Those are products that can be used on any type of lawngrass (as long as it’s mature and has been through its first winter), and beneath trees and shrubs as well.
Let me put this out there just a bit more emphatically. If you don’t want to have ugly annual bluegrass and similar grassy winter weeds in your lawn next February, March and April, you must apply pre-emergent granules between now and Labor Day. You do not get any kind of second chance.
The products that are most commonly sold in Texas nurseries, hardware stores and feed stores are Dimension, Halts and Balan for the grassy weeds and Gallery to prevent broadleafed weeds. There is no product that combines the two categories, so if you’re trying to prevent grassy weeds and broadleafed weeds, you will have to make two passes across your lawn to get the job done. Do not try to mix the products in your fertilizer spreader. Both can be applied on the same day, then both should be watered into the top layer of soil. Unlike the spring treatments, where you need to follow up with a second application 90 days later, just the one treatment made around Sept. 1 will be all that you’ll need. For the record, with broadleafed weeds, you do get a second chance. You can apply a broadleafed weedkiller containing 2,4-D late in the fall, before winter rolls in to stay, to eliminate the young plants as they begin to grow. But with grassy weeds, you don’t get that chance. There is no follow-up product available.
I’m also being asked repeatedly how late in the season new grass can be started, so I’ll address that question for everyone. It depends on where you live in Texas, of course, but I prefer to have bermuda planted from seed no later than Sept. 1 (preferably earlier). The same goes for sodding St. Augustine, especially in the northern half of the state. Zoysia and bermuda can be sodded later, but they really benefit from being planted while the soils are still warm so they can establish good root systems before winter.
So those are the questions I’ve been getting by the dozens each week. I feel better having addressed probably 25 of you who are waiting in the queue now, if only as a group reply. I’ll go back to my normal Q&A format next week. If you’ve been waiting for me to address a specific question you’ve sent me, please accept my apology for the additional delay. It seemed to be the only way I would ever get caught up.
If you’d like Neil Sperry’s help with a plant question, drop him a note in care of The Eagle, P.O. Box 3000, Bryan, Texas 77805. Or email him at firstname.lastname@example.org.
Be the first to know
Get local news delivered to your inbox!