Mixing tall fescue species still best bet
At some point in our lives, we have all been warned: “If it is too good to be true, then it probably is.” As discerning shoppers, we heed this warning when looking for a used car, dialing the phone to order from a late-night infomercial, or buying investment property in some other part of the country. Often, with a little research, we can uncover the deals and avoid the dogs that result in years of financial frustration.
Now we can add one more item to the “if it is too good to be true” list. Rhizomatous Tall Fescue, or RTF, is gaining in popularity with local retail chains and radio talk show hosts. But buyer beware: RTF may not be as green and lush as they make it sound. Here is what you need to know about sowing and growing RTF in our area.
Rhizomes are underground vegetative stems that allow grass plants to spread. This is a desirable characteristic because a thinning stand, over time, can grow lush and thick again. All tall fescue varieties have mini-rhizomes, but there are some that have more aggressive rhizomes than others. The newest of these varieties are called rhizomatous tall fescues or RTF types.
Researchers at Kansas State University are in the process of testing these grasses to see how well they grow in Kansas conditions. Results from the studies are still a growing season away, so no official recommendations have been made. However, there are some preliminary findings from a study conducted at Ohio State University that have proven to be quite interesting.
Ohio State research tested six different RTF varieties: Labarinth RTF, Grande II, Titan Ltd., Rendition, Kittyhawk 2000 and Winter Active Fescue. As with all research, there is good news and bad news.
First the good news. Critics of RTF varieties have argued in the past that some varieties of RTF were open-growing and did not have high density. In this study, researchers noted that several varieties had high density, excellent color and a fine leaf texture – all desirable traits for a home lawn. This was particularly true of Winter Active and Grande II.
And now for the bad news. Previous claims from other sources have suggested that RTF varieties experienced as much as 90 to 95 percent rhizome growth activity. However, Ohio State research revealed that rhizome activity was much less. The rhizome activity was less than 15 percent for all of the varieties tested. The differences seemed to be related to planting density and the amount of soil compaction. Spaced plants on noncompacted soil showed the most rhizome activity.
Results of a dense planting with real-world compacted soil conditions showed Winter Active Fescue had 12.3 percent activity. A blend of Titan Ltd., Rendition and Kittyhawk 2000 gave 13 percent rhizome development. Grande II by itself had 11 percent. Labarinth RTF experienced 10 percent. Rendition came in last with only 6 percent rhizome activity.
The take-home message from this research is not to plant only RTF varieties of turfgrass and expect them to fill in like a zoysiagrass lawn. But rather, continue to plant a mix or blend of several different species of tall fescue. And above all, manage the lawn using responsible and environmentally friendly cultural practices.