Spring is a busy time in the gardening world, and I never feel like I have enough time in the day to get to all my garden tasks. It could be that I need to stop buying plants for my new flower beds and just focus on what I have already growing, but where is the fun in that? Planting flowers is more fun than pulling weeds!
One topic that is coming up a lot this spring is problems in the lawn. St. Augustine grass took a hard hit in many lawns this winter, and it is very slow to come back this spring.
This winter, we had relatively warm weather until the hard freeze in January. Many St. Augustine lawns were still green in January and had not had enough cold temperatures to go dormant. During the hard freeze on the weekend of January 13, we had temperatures down to 17 degrees. That is a big temperature drop for St. Augustine grass that has not gone dormant yet!
If you have St. Augustine grass on a north-facing lawn or a north-facing slope, that kind of cold weather can severely damage the grass. Be patient this spring and see if the St. Augustine grass comes back to life as soil temperatures warm up. We have still had nighttime temperatures in the 40’s over the last week, so give the soil a little more time to warm up before you give up all hope. If the grass does not green up in the next few weeks, you might need to consider replacing it.
Another common spring problem in St. Augustine lawns is Take All Root Rot. I have not seen much of this fungal disease yet, but the cool, rainy weather we are experiencing could kick-start the fungus into action.
The symptoms of take-all root rot usually appear in spring and early summer with yellowish grass that eventually turns brown and wilts. The turfgrass thins and leaves brown patches that range in size from one foot to more than 20 feet in diameter. As you can imagine from the name of this fungus, the roots of infected grass turn black and rot.
Take-all root rot lives in the thatch layer of turfgrass, the layer of roots, stolons, and decaying plant matter that lives at the soil surface. The fungus is always present but takes advantage of turfgrass that is under stress from environmental conditions like too much shade, water, or extreme temperatures.
Good lawn management practices can help with Take All Root Rot. Water only when the grass needs supplemental irrigation. We have had enough rain this spring, that you do not need to turn your sprinklers on yet. Conduct a soil test to determine how much fertilizer your lawn needs. Too much fertilizer will contribute to fungal growth, so only apply what is required. Grass clippings and an application of compost might be all the fertilizer your lawn needs.
You probably need to apply a fungicide this spring if you have had Take-All Root Rot in your lawn in the past. Try to apply the fungicide containing azoxystrobin, myclobutanil, or propiconazole before new symptoms appear this spring. Follow the label instructions and water the product into the lawn.
If you have had trouble with Take All Root Rot or Large Patch in the past, consider aerating your lawn with a hollow-tine aerator to increase oxygen availability to the roots and improve water infiltration. Follow up with a top-dressing of ¼ to ½ inch of compost to the lawn to add organic matter and nutrients.
For more information about trees or other lawn and garden topics, contact the Williamson County AgriLife Extension Office at 512-943-3300.
