Taking an environmentally sensitive approach to pest management
Published: August 19, 2014
When many individuals hear the grass specie “tall fescue”, they envision a course, clumpy grass they see in pastures. To many, this is undesirable for a home lawn. While there is plenty of K-31 grass seed available and often sold as a lawn seed, more desirable tall fescues are available for establishing a fine lawn.
Three types of fescue should be mentioned before we get into a discussion about what to select. The K-31 tall fescue (Festuca arundinacea) is considered a forage-type fescue and is seen along Missouri roadsides and in Missouri pastures. It is by far the most prominent grass seen across Missouri and the U.S. Missouri still manages to harvest a half-million to a million acres of lower quality fescue seed each year. Many retailers will usually carry it in 50 pound bags on pallets at their front doors. It is relative cheap ($0.85 to $1.00/lb) when compared to other turf-type fescues and it does have a place as a lawn type grass. Where larger acreage is being maintained, like parks and large grassy landscapes; forage-type fescues seeded at 10 pounds per 1,000 square feet can provide excellent cover when mowed at 4-inches. Higher seeding rates create a crowding effect that makes this grass appear finer in texture. If that high density can be maintained with over-seeding; then the large clumpy, coarse appearance can be controlled. It can be used on steep banks, along driveways and ditches. It is a bunch-type grass that does not spread. It does product tillers (additional shoots that develop from the crown) to increase canopy density. It tends to form the large clumps when thinned by disease, insects or drought.
Fine fescues are often described for the turf-type fescues when obviously compared to the coarser forage-type fescues. However, fine fescues are a class of fescues by themselves different from the turf-type fescues and worth mentioning. The fine fescues are extremely fine-leafed fescues that are composed of several species. They include creeping red fescue (Festuca rubra), chewing fescue (Festuca rubra ssp. commutata), hard fescue (Festuca tryachphylla), and sheep fescue (Festuca ovina). The fine fescues, with very slender leaves, adapt better to low light conditions, such as shade. These fescues are often recommended for shade seed mixtures, but keep in mind that under extreme shade conditions (full-shade all day); no cool-season grass can flourish. Many feel that their grasses are getting sufficient sunlight but do not realize that filtered sunlight through tree canopies is not sufficient and turfgrasses will thin out.
Turf-type tall fescues are the most improved tall fescues and are used primarily for lawn use. They have been developed by seed companies to provide a finer textured leaf blade – somewhere between the forage-type and fine fescues previously mentioned. Their leaf blades are slightly wider than a Kentucky bluegrass. Color is usually a deep emerald green and many of the newer varieties will provide some disease resistance to brown patch. While the turf-type fescues have been considered a bunch-type grass in general; recent developments have provided several rhizomatous tall fescue (RTFs) varieties producing short rhizomes allowing some spreading capabilities. Several new varieties of RTFs are currently available on the market. Other RTFs may have a slightly different identifier indicating rhizomatous capabilities. Some are noted with an RZ after the variety name for RhiZamotous (e.g. – Turbo RZ Cezanne RZ), others an LS for Lateral Spreading (e.g. – Spyder LS, Firecracker LS, and Titanium LS), and SRP for Self-Repair Potential (e.g. – Rhambler SRP and 3rd Millennium SRP). Blend and/or mixtures containing any of the RTFs have no downside in using them. While some of the more advanced RTFs do have short rhizomes; observations also indicate that these tall fescues seem to tiller more improving canopy density for weed competition.
Fescues, in general, are more deeply rooted than all other cool-season grasses like bluegrasses and ryegrasses. This allows for better heat and drought tolerance during a Missouri summer. Requiring less water than bluegrass or ryegrass keeps them from greener longer with the onset of droughts. Fescues are recommended in lawns when irrigation is not a choice or option. Establishment rates for fine and turf-type fescues are 6 to 8 pounds per 1,000 square feet. Mowing heights are best at 3.5 to 4 inches high. Brown patch (Rhizoctonia solani) is the most important disease limiting tall fescue use in Missouri. The disease occurs during the summer and follows the “6-8 flip-flop” rule, with conducive temperatures being a nighttime low near 68 degree F and daytime highs near or above 86 degrees F. Disease symptoms will vary according to mowing height. Brown patch on higher-cut turfgrass (lawn height of 3.5 to 4 inches) appears as brown or straw-colored round patches 6-inches or more in diameter. A characteristic irregularly shaped straw-colored lesion with a dark brown margin can be seen on newly infected leaves along the margin of patches. When fescue is wet in the early morning, tufts of pathogen mycelium may be seen scattered along patch margins (Fresenburg et al., 2013).
Blends and Mixtures:
Blends (three to four varieties in equal portions) of turf-type tall fescues can give deep emerald green appearances with a slightly coarser texture than Kentucky bluegrasses. They tend to be a deeper rooting plant, therefore requiring less water than a bluegrass lawn. They are not as susceptible to dollar spot and summer patch, but generally will require some fungicides for the control of brown patch disease. Several varieties of turf-type tall fescues offer superior resistance to brown patch and therefore will improve turf quality. Tall fescues will tiller to help with recovery, but tend to be clumpy with severe thinning. They also grow well in full sun to partial shade.
Mixtures, such as turf-type tall fescues (in a blend) with Kentucky bluegrasses (90 percent fescue, 10 percent bluegrass), combine the advantages or strengths of each species to mask the weaknesses of the other. Any grass seed mixture with perennial ryegrass should not exceed 20 percent perennial ryegrass, as it is susceptible to most of the diseases list above. Ryegrass is not very heat or drought tolerant and does not recover from thinning of cover. Unfortunately, many seed mixtures and blends available to homeowners at local garden centers contain large amounts of ryegrass (both annual and perennial) and fine-leaf fescues (creeping red fescues, hard fescues, etc.). Fine-leaf fescues have little tolerance for direct sunlight.
So which varieties do you select once you decide on a blend or mixture to plant? Various resources provide recommendations for turfgrass varieties for Missouri. Garden centers, MU Extension publications, turfgrass specialists, and other lawn care experts are good sources for information about turfgrass selections. The difficulty for most individuals is to find the varieties suggested. We will discuss several options.
Selecting Seed Products/Varieties:
The number of seed products being sold over-the-counter can be overwhelming. However, by looking at the seed tags on products, the selections can be narrowed. Keep in mind that seed products are packaged for national sales and are excellent products for many areas of the country. However, that does not mean that all seed products grow well in all areas of the country. Missouri weather can be very limiting for some species. Concentrate more on the products that are tall fescue and Kentucky bluegrass blends or mixtures of tall fescue and Kentucky bluegrass.
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REVISED: September 17, 2018