Cynodon dactylon

Cynodon dactylon
Scientific classification
Kingdom: Plantae (unranked): Angiosperms (unranked): Monocots (unranked): Commelinids Order: Poales Family: Poaceae Genus: Cynodon Species: C. dactylon
Binomial name
Cynodon dactylon (L.) Pers.

Cynodon dactylon (syn. Panicum dactylon, Capriola dactylon), also known as dūrvā grass, Bermuda Grass, Dubo, Dog's Tooth Grass, Bahama Grass, Devil's Grass, Couch Grass, Indian Doab, Arugampul, Grama, and Scutch Grass, is a grass native to north Africa, Asia and Australia and southern Europe. The name "Bermuda Grass" derives from its abundance as an invasive species on Bermuda; it does not occur naturally there.

The blades are a grey-green colour and are short, usually 4–15 cm long with rough edges. The erect stems can grow 1–30 cm (rarely to 90 cm) tall. The stems are slightly flattened, often tinged purple in color. The seed heads are produced in a cluster of 3–7 spikes (rarely two) together at the top of the stem, each spike 3–6 cm long. It has a deep root system; in drought situations with penetrable soil, the root system can grow to over 2 m deep, though most of the root mass is less than 60 cm under the surface. The grass creeps along the ground and root wherever a node touches the ground, forming a dense mat. C. dactylon reproduces through seeds, through runners and rhizomes. Growth begins at temperatures above 15°C (59°F) with optimum growth between 24°C to 37°C (75–99°F); in winter the grass becomes dormant and turns brown. Growth is promoted by full sun and retarded by full shade, e.g., close to tree trunks.

Cultivation and uses

C. dactylon is widely cultivated in warm climates all over the world between about 30° south and 30° north latitude, and that get between 625–1,750 mm (25–69 inches) of rainfall a year (or less, if irrigation is available). It is also found in the U.S. mostly in the southern half of the country and in warm climates. It is fast growing and tough, making it popular and useful for sports fields, as when damaged it will recover quickly. It is a highly desirable turf grass in warm temperate climates, particularly for those regions where its heat and drought tolerance enable it to survive where few other grasses do. It has a relatively coarse-bladed form with numerous cultivars selected for different turf requirements. It is also highly aggressive, crowding out most other grasses and invading other habitats, and has become an invasive species in some areas. This invasive nature leads some gardeners to give it the name of "devil grass".

Control

Chemical Control of Established Plants

Bermudagrass can be controlled in ornamental landscapes and turf with postemergent herbicides. Postemergent herbicides are applied to actively growing bermudagrass foliage and stems during spring and summer. The best time to apply a particular postemergent herbicide depends on the type of herbicide and the situation where the weedy bermudagrass is growing. There are two basic types of herbicides that can kill mature bermudagrass, nonselective herbicides that kill most plant species and grass-selective herbicides that only kill plants in the grass family (Poaceae). In addition, there are some herbicides that will suppress bermudagrass, which might give a desirable turf species a chance to outcompete the weed.

Grass-Selective Herbicides. These herbicides include the active ingredient sethoxydim (Grass Getter), fluazifop (Fusilade, Ornamec, and Grass-B-Gon), or clethodim (Envoy). Fusilade and Envoy are only available for sale to licensed pesticide applicators, the others are sold in most retail garden outlets. This is not a complete list of all retail products; look for similar herbicides with the same active ingredient.

Early spring is the best time to apply a grass-selective herbicide. For best control with these herbicides, make the first application in spring when new bermudagrass growth is less than 6 inches in length, then re-apply the herbicide before the regrowth reaches 6 inches again. Additional applications on regrowth may be needed through the spring and summer. It is important to be consistent with treating regrowth in order to eliminate the weed, but read the label of each product for information on the total amount that can be used per year per area. The best control is achieved when the bermudagrass is growing vigorously, has lots of leaf surface and is not drought stressed, is not dusty, and has not been damaged by insects.

Treating Around Ornamentals and in Turf. These herbicides can be used safely around most, but not all, ornamental trees, shrubs, and flowers. The product use labels include lists of ornamental plants that can be injured by these herbicides. Do not use these herbicides near ornamental grasses. The herbicide Fusilade can be used to kill bermudagrass in fescue turf when label conditions are followed.

Nonselective Herbicides. Glyphosate (Roundup and other brand names) is a nonselective herbicide that kills plants by translocating down into the root system, in addition to killing top-growth. For glyphosate to be most effective it must be applied to bermudagrass that is vigorously growing, not drought stressed, and has lots of leaf surface (do not mow the weed for 2 to 3 weeks before treating). The best time of the year to apply glyphosate is during late summer when the plant is storing food in the roots. Wait 7 days after applying to mow or cultivate the bermudagrass. Cultivation will bring the underground parts of the plant (stolons and rhizomes) to the surface of the soil so they can dry. If left uncultivated, deeper rhizomes and roots may survive the first application and regrow.

Other Herbicides. Some herbicides will suppress bermudagrass by killing green stems and leaves. Suppressing bermudagrass will not typically eliminate it permanently from an area, because there is no effect on the rhizome system, but it might be enough to foster the growth of a desirable turf species. Rigorous, repeated suppression may eliminate the weed if combined with control of bermudagrass seedlings.

Herbicides that can suppress bermudagrass include nonselective contact herbicides such as diquat (sold mostly in formulation with other herbicides), pelargonic acid (Scythe), other fatty or weak acids, and glufosinate (Finale). These herbicides can be used in ornamental and turf situations, but they will also injure desirable vegetation that they contact. Triclopyr (Weed-B-Gon and Turflon) is a selective herbicide that kills broadleaf plants, but will suppress bermudagrass in cool season turfgrasses.

Controlling Bermudagrass Seed

Following the treatment of a stand of established bermudagrass, bermudagrass seed that is present in the soil can still be a problem. Bermudagrass seed will not be controlled with any of the previously mentioned treatments except solarization.

Treating Around Ornamentals. If bermudagrass seeds germinate in areas around ornamental plantings, the seedlings can be controlled with shallow cultivation, hoeing, or a thin layer of mulch.

Treating Turfgrass. Bermudagrass seedlings may emerge in turfgrass that has been treated with postemergent herbicides because postemergent herbicides do not control the seed. On recently planted or established cool-season turfgrass, herbicides can be used to selectively control germinating bermudagrass seed without injuring the turfgrass. Apply a product containing siduron at the time of planting the turfgrass; DCPA (available to licensed pesticide applicators only), trifluralin (Treflan), pendimethalin (Halts, Pendulum), or oryzalin (Surflan) can be used when the turfgrass is greening. Dithiopyr (Dimension) and prodiamine (Barricade, which is available to licensed pesticide applicators only) can be used in established turf. To effectively control new seedlings, apply these herbicides before the seeds germinate. Because bermudagrass seed is viable in the soil for 2 years, apply the herbicide each year for 2 years.

Do not use preemergent herbicides, except those containing siduron, just before seeding or sodding a new lawn because they also affect germination of the desired grass species.

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