Tuesday, April 1, 2008

Turf - Rhizomatous Tall Fescue

Varieties of turf type tall fescue are being developed that have stronger rhizomes than previous varieties. These are called Rhizomatous Tall Fescue (RTF tall fescue) This should give the ability to develop a denser, more wear resistant turf. Evaluations of these varieties to date show good promise. However, it can take considerable time (a year or more) for significant rhizome development. The following is an article on RTF tall fescue.

Rhizomatous Tall Fescue Varieties

Rhizomes are underground stems that allow a grass to spread. Therefore, a rhizomatous grass is desirable because it can thicken the stand if it thins. All tall fescue varieties have mini-rhizomes but there are some that have more aggressive rhizomes than others. Often these are called rhizomatous tall fescues or RTF types.

We already have some preliminary findings from a study done at Ohio State University. The varieties included in the Ohio study were Labarinth RTF, Grande II, Titan Ltd., Rendition, Kittyhawk 2000 and Winter Active Fescue. It has been noted in the past that some RTF varieties were open growing and did not have high density. In this study, it was observed that several varieties had high density, excellent color and a fine leaf texture. This was particularly true of Winter Active and Grande II. That’s the good news. The bad news is the amount of rhizome activity. Initial research suggested 90 to 95 percent rhizome activity. However, this study revealed that rhizome activity was much less than previously thought; less than 15 percent for all varieties. The differences seemed to be related to planting density and the amount of compaction. Spaced plants on noncompacted soil showed the most rhizome activity.

Results on a dense planting with native soil (real-world 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 had 11 percent; Labarinth RTF came in at 10 percent; and Rendition had only 6 percent. Though these results are much less than initially thought, any increase over standard types might have an effect on certain desirable characteristics such as wear tolerance.

Wear tolerance is the ability of a grass to withstand traffic. This factor was also measured in this study. Recuperation from this stress was deemed to be better with RTF types than other varieties with the best RTF variety being Grande II.

Though these results suggest that RTF types may have some advantages (recuperation from wear tolerance), we need further data ditions to make firm recommendations.

Adapted from "Rhizomatous Tall Fescue Varieties" from the March 7, 2007 edition of the Horticulture Newsletter from Kansas State University.

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