Richard L. Duble, Turfgrass Specialist
Texas Cooperative Extension
Text and images copyright © Richard Duble.

Bermudagrass (Cynodon spp.) is a major turf species for sports fields, lawns,
parks, golf courses, and general utility turfs in Australia, Africa, India,
South America and the Southern region of the United States. It is found in over
100 counties throughout the tropical and subtropical areas of the world. Common
bermudagrass, C. dactylon, naturalized throughout the warmer regions of the
United States, was introduced into this country during the colonial period from
Africa or India. The earliest introductions are not recorded, but bermudagrass
is listed as one of the principal grasses in the Southern States in Mease's
Geological Account of the United States published in 1807.

The genus Cynodon comprises nine species with C. dactylon being the most
widespread. That C. dactylon is a tetraploid with broad genetic variability
serves to explain its widespread distribution. Other Cynodon species have a
more limited natural distribution and are often restricted to one particular
habitat. C. dactylon is highly fertile, whereas the diploid species such as C.
transvaalensis rarely produce viable seed.

C. dactylon (L.) Pers is commonly called bermudagrass in many areas of the
world. But, it is also known by numerous other names including "Kweekgras" (S.
Africa), couch grass (Australia and Africa), devil's grass (India) and
gramillia (Argentina). The variety of names given this species attests to its
wide distribution and to the fact that it is the object of abuse and scorn.

In addition to being a widely used species for forage and turf, C. dactylon is
a serious weed in many crops. Being a vigorous, stoloniferous grass, it rapidly
invades crops in high rainfall or irrigated areas. C. dactylon is ranked among
the three most troublesome weeds in sugarcane, cotton, corn and vineyards in
many countries. It is a difficult weed to eradicate because of its seed
production and deep rhizomes.

In the United States the distribution of bermudagrass extends from New Jersey
and Maryland southward to Florida and westward to Kansas and Texas. Under
irrigation its distribution extends westward to southern New Mexico, Arizona
and to most major valleys in California. The development of more cold tolerant
turf-type varieties of bermudagrass such as U-3 and Midiron has increased
interest in the species near its northern limits. Low winter temperature is the
factor that limits the northward distribution of bermudagrass.

Description. Bermudagrass (C. dactylon (L.) Pers.) is a highly variable, sod
forming perennial that spreads by stolons, rhizomes and seed. Stolons of
bermudagrass readily root at the nodes. Lateral buds develop at the nodes to
produce erect or ascending stems that reach 5 to 40 cm (rarely over 90 cm) in
height. In most Cynodon sp., leaves are borne on stems with long internodes
alternating with one or more very short internodes. This characteristic gives
the impression that the species has multiple-leaved nodes. Leaf sheaths are
compressed to round, loose, split, smooth, sparsely hairy, up to 15 cm long,
and with a tuft of hairs 2 to 5 mm long. Auricles are absent. Collar is
continuous, narrow, glabrous and hairy on margins. Leaf blades are 2 to 16 cm
long, 1.5 to 5 mm wide, smooth to sparsely pubescent, folded or loosely rolled
in the bud and sharply-pointed. The inflorescence consists of 3 to 7 spikes in
a single whorl in a fingerlike arrangement and 3 to 10 cm long. In robust forms
there may be up to 10 spikes, sometimes in two whorls. Spikelets are 2 to 3 mm
long, in 2 rows tightly appressed to one side of the rachis; glumes are to °
the length of spikelet; lemma is boot-shaped, acute with fringe of hairs on the
keel and longer than the glume; seed is 1.5 mm long, oval, straw to red-colored
and free within the lemma and palea.

Bermudagrass has a fibrous, perennial root system with vigorous, deep rhizomes.
Roots are produced at the nodes after new leaves or tillers are produced during
the growing season and after new shoots are produced in the spring. Mature
roots are yellow to brown while new roots are white. Mature roots deteriorate
throughout the growing season and new roots are produced continuously. Root
production and dieback has been reported to be particularly high in the spring
at the onset of shoot production.

Adaptation and Use. Bermudagrass is a warm season perennial species adapted to
tropical and subtropical climates. It grows best under extended periods of high
temperatures, mild winters and moderate to high rainfall. Temperature is the
main environmental factor that limits its adaptability to tropical and
subtropical areas of the world. The northern limits of bermudagrass extend into
the transitional zone of the United States where low temperatures seldom drop
below 10°F. In general, temperatures below 30°F kill the leaves and stems of
bermudagrass. Research has demonstrated that bermudagrass will continue to grow
with night temperatures as low as 34°F if day temperatures are near 70°F.
However, when average temperatures drop below 50°F growth stops and the grass
begins to discolor. At the onset of low temperatures in the fall and winter,
bermudagrass begins to discolor, protein fractions change in composition and
reserve carbohydrates increase in the stems and rhizomes. After the first
killing frost, leaves and stems of bermudagrass remain dormant until average
daily temperatures rise above 50°F for several days. The roots and rhizomes of
bermudagrass continue to grow several weeks after the leaves and stems stop
growth.

In warm frost-free climates bermudagrass remains green throughout the year, but
growth is significantly reduced at the onset of cool nights. The species makes
the best growth where average daily temperatures are above 75°F. Optimum
daytime temperature for bermudagrass is between 95° and 100°F.

Soil temperature, as influenced by air temperature, is also important to the
growth and development of bermudagrass turf. Soil temperatures above 65°F are
required for significant growth of rhizomes, roots and stolons. Optimum soil
temperature for root growth is around 80°F.

Bermudagrass has a high light requirement and does not grow well under low
light (shaded) conditions. The duration of the light period (day length) also
influences growth and development of bermudagrass. Both increased light
intensity and day length increase rhizome, stolon and leaf growth in
bermudagrass. At low light intensities (less than 60% full sunlight)
bermudagrass develops narrow, elongated leaves; thin upright stems; elongated
internodes and weak rhizomes. Consequently, bermudagrass develops a very sparse
turf under moderately shaded conditions.

Bermudagrass is found in tropical and subtropical climates with 25 to 100
inches of annual rainfall, but it also survives in arid climates along
waterways and in irrigated areas. Where annual rainfall is below 20 inches per
year, bermudagrass requires irrigation to survive. Bermudagrass develops into a
semidormant state during very dry conditions, but has the capability of
surviving extreme droughts. Rhizomes of bermudagrass can lose 50% or more of
their weight and still recover when favorable moisture develops. Generally,
common bermudagrass, or tetraploids of C. dactylon, have the deepest root and
rhizome penetration and better withstand prolonged drought periods.

Common bermudagrass also has the characteristic of producing seedheads under
stress conditions such as drought. Thus, the seeds provide another method by
which the species can survive extreme drought. Some natural biotypes of C.
dactylon produce numerous seeds. The seeds are very small with about 2,000,000
seeds per pound.

Bermudagrass grows well on a wide variety of soils from heavy clays to deep
sands, provided fertility is not limiting. It tolerates both acid and alkaline
soil conditions and is highly tolerant to saline conditions. Bermudagrass
survives some flooding but does best on well-drained sites. Although it may
persist under low fertility, bermudagrass has a high nitrogen requirement for
good quality turf.

Bermudagrass has numerous turf uses. It has been suggested that if ever a plant
deserved a monument for its service to mankind, it was bermudagrass for what it
has done to prevent soil erosion, to stabilize ditch banks, roadsides and
airfields, to beautify landscapes and to provide a smooth, resilient playing
surface for sports fields and playgrounds. Bermudagrass also provides hay and
pasture for livestock throughout the tropical and subtropical areas of the
world.