Thoughts on tall fescue and other cool-season turfgrasses

Work continues on developing tall fescues that establish better — getting them up and getting them going. We’re also working on improving their density, compactness and color retention.

Another reason tall fescues are popular is that they have the ability to survive the summertime heat. If they’re irrigated at all in the summer they have the ability to re-root, even when attached by grubs. A ryegrass that gets chewed up by grubs starts to wilt even if it’s watered. Most of these new tall fescues have a lot of endophyte, but that doesn’t control grubs because there’s no endophyte in the root system. Yet, the tall fescues seem tolerant of grubs.

In general, fine fescues require less irrigation than tall fescues, but tall fescues are able to secure water from deep roots. Bluegrass is next in terms of irrigation, and ryegrass needs the most water.

Tall fescues like to be fertilized but they don’t require the fertilizer that ryegrass does to stay dense. Tall fescue does require more fertilizer than fine fescue, which holds its density with less fertilizer. Fine fescues require one to two pounds of nitrogen a year, tall fescues about three to four pounds and bluegrass and ryegrass four to six pounds. If we fertilize fine fescues too much they get puffy with too much thatch.

A lot of people will put in a mixture of fine fescue, Kentucky bluegrass and ryegrass. They’ll fertilize it when it goes in and then they forget about fertilizing and end up with all fine fescue after five or six years. If you don’t fertilize ryegrass four times a year it’s going to thin out and not do well. Bluegrass is the next best at low maintenance because it stores carbohydrates in rhizomes.

The big advantage fine fescues has is that we now have the new endophytes that are conveying disease resistance and they (fine fescues) are more heat tolerant and higher quality. At least one-third of the collections we now do in Europe have a good endophyte level.

Of the fine fescues, strong and slender creepers come up pretty fast and establish the quickest with chewings next and hard fescue the slowest. The thing we like about strong creepers is if we do have a severe summer with drought conditions the rhizomes give them the ability to recover in the fall.

Because we now have better creepers and better chewings types, it would be wise for lawn care companies to include them in lawn mixtures, especially where there is a lot of shade.

Biodiversity is another strategic reason to include strong creepers with ryegrass and bluegrass in equal amounts by weight in sod and turf mixes. Ryegrass and strong creepers resist summer patch, unlike bluegrass which is susceptible to it. Chewings is a little more susceptible, and hard fescue will get summer patch when over-fertilized or the soil is compacted. Where ryegrass gets pythium, bluegrass and fine fescue survive. Fine fescues tolerate poor soil quality better than ryegrass, and endophytes in fine fescue help us reduce pesticide use.

Few people know about the summer patch resistance of strong creepers. We know that it’s useful in a mix because summer patch is a major problem in bluegrass.

While tall fescues are approaching the density and appearance of Kentucky bluegrass, and brown patch has been reduced, they are not perfect yet. Including 5% Kentucky bluegrass by weight is still recommended. Bluegrass rhizomes improve lateral strength of the turf and resist winterkill, although winterkill is not so much of an issue with tall fescue anymore. Also, in a mixture, you can’t kill strong creepers with ice sheets, but ryegrass is susceptible to winterkill.

Now that we’ve changed the density of tall fescues, we need to rethink blending procedures. If tall fescues have different genetic backgrounds it’s worthwhile, but not necessary, to blend them. Ryegrass will still out-compete tall fescue if seeded together.

The cool-season/warm-season areas of adaptation borders are getting fuzzier. The Bermudagrass people are trying to come north and the cool-season people are trying to go south. The problem with Bermudas in the cool-season areas is if they stay green late, they winterkill. If they go dormant early they’ll do fine. Zoysia does great, but most people are unhappy with it because it only stays green during June, July and August so it’s fine around beach homes where it doesn’t matter if it goes brown in September.