Cover Story
Encroachment of Annual Grass into Turf —
Basic Turf Management Is Still the Key By Tom Turner, Ph.D., University of Maryland
Table 1. Annual grass encroachment into University of Maryland recommended turfgrass mixtures* vs. commercially sold non-recommended mixtures. Seed Mixture Name
Species
Cultivars
Annual Grass Encroachment % of seed mixture
% cover
25% 25% 25% 25%
3%
Univ. of MD Recommended Tall Fescue
Turf-type tall fescue
Davinci* Picasso* Rembrandt* Masterpiece*
Univ. of MD Recommended Tall Fescue
Turf-type tall fescue
Justice* Rebel Exeda* Penn 1901*
49% 29% 20%
8%
Sunny Mix
Turf-type tall fescue Turf-type tall fescue Red fescue
Reserve Starfire Boreal
53% 34% 10%
25%
Contractor’s All Purpose
Italian ryegrass Red fescue Perennial ryegrass Kentucky bluegrass
Panterra Bargena III Prelude IV Clearwater
40% 29% 18% 9%
53%
Kentucky 31 Fescue
Tall fescue
Kentucky 31
95%
50%
Sun and Shade
Perennial ryegrass Perennial ryegrass Red fescue Kentucky bluegrass
Majesty* Splendid Crossbow Abbey
30% 20% 25% 25%
47%
* Cultivars with an asterisk were on the Maryland recommended list at the time these plots were established in fall 2008.
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MTC Turf News
A
nnual grass encroachment into turfgrass continues to be one of the major problems affecting turfgrass managers in the Mid-Atlantic region. In the last 30 years, much research has been conducted to investigate the efficacy of pre- and post-emergence herbicidal control programs for crabgrass, goosegrass and foxtails. Excellent control (95% or better) has been achieved through proper use of annual grass herbicides, and they continue to be an important, and often necessary, tool for professional turfgrass managers. However, attention to basic turfgrass management can often greatly minimize potential annual grass problems and thus reduce the need for and the frequency of herbicide applications. Annual grass encroachment into turfgrass is primarily a function of turfgrass density. The denser the turf, the more difficult it is for germinating annual grass plants to survive. Any practice that maximizes turfgrass density will greatly diminish the degree of annual grass encroachment. It should be noted that the encroachment of annual grasses and broadleaf weeds is not just an aesthetic issue: as these weeds die back after