Bermuda-Bentgrass Mixture grass combination resistant to heavy pedestrian traffic sought for use in public parks and recreational areas

Vernon T. Stoutemyer

The studies reported in the following article were conducted by Zaki Mahdi, a graduate student in Ornamental Horticulture, working under the direction of Professor Vernon T. Stoutemyer.

Two mixtures of grasses--Congres- dominance of the bentgrass-in a region ance of grain or matted turf. Correct sional bentgrass with U-3 bermudagrass where bermudagrass invades all turf management is essential with this combi- and Old Orchard bentgrass with the U-3 naturally-was unexpected. nation of grasses. bermudagrass-have proved to be resist- Fungicides were not applied to the The turf of the best combinations has ant to wear in experimental plantings. turf for the protection of the bentgrasses required so little attention and has had For further testing, these two combi- against turf disease. During attacks of an excellent appearance that it is seri- nations are being tried on a pitch-and- dollar spot-the most important turf ously suggested for permanent lawns in put course in one of the public parks disease in the locality-the infestation southern California since it is almost im- of Los Angeles where the heavy traffic was greatly reduced in the mixed turf possible to prevent the invasion of com- causes expense and great difficulty in of bentgrass and bermudagrass in com- mon bermudagrass in lawns of cool maintaining turfs of bentgrass. parison with the same strain of bentgrass season grasses. In southern California, where there alone. In the vicinity of Los Angeles, the use are many lawn bowling clubs, sometimes of a putting green mower on lawns of the traffic has been too severe for bent- bermudagrass and the removal of clip- grass greens, and in such cases the in- Combinations pings has eliminated the need for peri- troduction of bermudagrass has helped The all-year appearance of the mix- odic, mechanical renovation of the turf. to solve the problem. Occasionally com- ture of Congressional bentgrass and the Other combinations equal, or supe- mon bermudagrass may become an in- U-3 bermudagrass was outstanding, and rior, in performance may be developed vader in turfs of Seaside bentgrass. How- color and texture seemed well matched. through experimentation. Bentgrasses ever, the textures and colors of the two The combination of Old Orchard bent- which have survived on fairways in the grasses do not match well and a highly grass with U-3 bermudagrass proved to Lower San Joaquin Valley are being objectionable effect is produced. be equally desirable. used in an attempt to select strains with A series of experiments was started The mixtures of Collins bentgrass with unusual heat and drought resistance for in the spring of 1950, when equal quan- the Tifton 57 strain of bermudagrass and use in this type of mixture. tities of stolons of three strains of ber- Arlington bentgrass with the Tifton No. Results obtained thus far in the ex- mudagrass were mixed with three strains 12 bermudagrass were not satisfactory perimental plantings are sufficiently of creeping bentgrass and planted vege- in appearance and performance particu- promising to encourage cautious trial tatively. The grasses were mowed at put- larly at certain seasons of the year. This where heavy traffic is a problem or where ting green heights of cut, but with less indicates the vital importance of match- natural invasion of the turf by bermuda- than the usual regularity. ing suitable compatible strains of the two grass is serious. Fertilizer was used to apply nitrogen grasses. Experience in southern California has at the rate of 15 pounds per thousand The vigorous clonal strains of creep- shown that the U-3 bermudagrass will square feet per year. Attempts to reduce ing bentgrass and the finer-textured ber- eliminate or suppress common bermuda- the applications of nitrogen-particu- mudagrasses require similar mainte- grass. larly during the summer-always re- nance. Close mowing should be done at sulted in some loss of quality and density Zaki Mahdi is a Graduate Student in Orna- reasonable intervals, preferably with the mental Horticulturae, University of California, of the turf. Liberal applications of nitro- use of a rake or comb attachment on the Los Angeles. gen did not unbalance the proportion of mower. This will help to avoid the pro- Vernon T. Stoutemyer is Professor of Flori- the grasses at any season of the year. duction of matted turf and will postpone culture and Ornamental Horticulture, Univer- Sample plugs of the turf were taken the need for topdressing. An occasional sity of California, Los Angeles. with a one inch soil sampling tube. The vigorous raking or brushing before The above progress report is based on Re- plugs were removed to the laboratory mowing will largely prevent the app-ar- search Project No. 1471. where they were dissected, and the indi- vidual grass plants were identified and counted under a binocular microscope. Seasonal Change of the Population of Bermudagrass Plus Bentgrass Associations. Twelve samples were counted on each (Average number of plants per one inch plug) plot. The averages in August and Febru- Congressionol and Collins and Arlington and U-3 Bermuda llfton *57 Tifton #12 ary or May are shown for two seasons Date in the accompanying table. The excellent Bermuda Bent Bermuda Bent Bermuda Bent winter condition of the combination in May 1951 ...... 8.0 22.6 7.3 24.0 5.2 22.1 contrast to that of the U-3 bermudagrass Aug. 1951 ...... 11.0 30.9 11.7 35.8 11.3 33.1 alone was strikingly apparent. Feb. 1952 ...... 0.8 35.0 6.4 30.0 1.6 34.2 In all combinations, the bermudagrass Aug. 1952 ...... 9.4 33.3 13.8 30.8 11.5 22.8 increased regularly each summer and . Feb. 1953 ...... 1.2 33.3 10.7 20.1 9.0 9.7 declined during the winter. The marked

CALIFORNIA AGRICULTURE, NOVEMBER, 1953 13