The DeKalb Extension Garden Patch

At this time of year the Extension Master Gardener office gets a lot of questions about turf maintenance.  Here are a couple of answers:

My landscape areas are full of this nasty weed people call nutsedge, especially in the lawns. Our landscape company recommended a product called Basagran. They used it on a test area but I was not very impressed. The company says it requires two applications, but they won't guarantee anything. A local nursery recommended a product called Image. What do you think?

Nutgrass is one of the hardest weeds to eliminate but it can be done with persistence! Why is it so difficult to control? Because it produces runners and a hard woody nut underground that stores food reserves, and if you kill off the tops it just pushes out new top growth and continues to spread. First, you need to determine whether you have yellow nutgrass or purple nutsedge. Yellow has a folded, needle-like appearance at the tip while purple nutsedge leaves are a bit wider, gradually tapering to a point. Bentazon (Basagran) controls only yellow nutsedge.

The chemical imazaquin (Image) can be used to control both yellow and purple nutsedge in bermudagrass, centipedegrass, St. Augustine grass, and zoysiagrass, but not in fescue lawns. The very best nutsedge control can be gotten with halosulfuron (Manage), but I rarely see it for sale in retail stores. (It is available from Internet companies.) Image and Manage are absorbed by sedge roots so be sure to irrigate after application.

You must identify any weed before you attempt to control it, especially if you are considering chemical control!  -  Lynwood Blackmon, DeKalb County Extension Agent.

My fescue lawn looked great all spring but recently I have noticed brown circular spots on the grass. My neighbor told me that it was Brown Patch. If so how can I get rid of it?

Brown patch is most prevalent on fescue fertilized in the summer when night temperatures are above 68 degrees. The dead patches may start small but can grow and join together to make patches more than 3 feet apart. To control it, do not fertilize fescue heavily in summer and if you irrigate, do it in the very late evening. There are lawn fungicides available to control brown patch. Read the label carefully and use the rate and timing that is indicated.

But before you reach for the lawn fungicide, eliminate the other conditions. Since brown patch is associated with watering in the evening and watering too often, change your irrigation habits to one deep soaking per week in dry weather.  If you feel sure the spots are caused by a disease, spray with a fungicide like propiconazole (Banner Maxx), mancozeb (Dithane) or myclobutanil (Immunox).
Changing the conditions that cause brown patch is not easy, but once you see the price of a bottle of fungicide you'll reconsider the effort. Remember that summer fertilization, drought stress, constant wetness and hard soil all predispose fescue to disease. Fescue does better in part sun and you need to mow high in the summer weather!  -  Lynwood Blackmon, DeKalb County Extension Agent

And a question about trees:

Why are native trees not considered invasive when they often spread and proliferate as rapidly as the exotics?

Good question! Everyone has their own ideas as to what “desirable species” are. Many exotics like the sawtooth oak, for instance, make excellent shade trees and are useful in urban areas. Unfortunately, some people believe it is a problem because they readily grow from seed, as do most native oaks. Most plants, like most people, have their good and their bad characteristics so how do we decide what makes a plant useful and what makes it a nuisance pest?  Send us your thoughts!  -  Gary Peiffer, DeKalb County Extension Agent

 If you have questions for us please use the Comments box, or email or phone the Master Gardener office:  dekalbmastergardener@dekalbcountyga.gov or 404-290-4080

Please respond to this reader survey - it's short!

Do you read our DeKalb Extension articles every week? Yes or No

Do you share the column with gardening friends? Yes or No

Is this information useful? Yes or No

What other types of information would you like that would help you with your gardening?

Please send survey responses to:  abonsall@dekalbcountyga.gov