''Digitaria didactyla'' is a species of

grass Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family (biology), family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and spe ...

known by the common names blue couch, Queensland blue couch, blue serangoon grass, green serangoon grass, blue stargrass, and ''petit gazon'' (in

Mauritius Mauritius, officially the Republic of Mauritius, is an island country in the Indian Ocean, about off the southeastern coast of East Africa, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Ag ...

).Cook, B. G., et al
''Digitaria didactyla''.
Tropical Forages. CSIRO, DPI&F (Qld), CIAT and ILRI, Brisbane, Australia. It is native to Mauritius,

Réunion Réunion (; ; ; known as before 1848) is an island in the Indian Ocean that is an overseas departments and regions of France, overseas department and region of France. Part of the Mascarene Islands, it is located approximately east of the isl ...

, parts of mainland Africa, and

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

.''Digitaria didactyla''.
Grassland Species Profiles. FAO. It has been introduced widely outside its native range, mainly for use as a

pasture Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Types of pasture Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, c ...

and

turf Sod is the upper layer of turf that is harvested for transplanting. Turf consists of a variable thickness of a soil medium that supports a community of turfgrasses. In British and Australian English, sod is more commonly known as ''turf'', ...

grass. It has

naturalized Naturalization (or naturalisation) is the legal act or process by which a non-national of a country acquires the nationality of that country after birth. The definition of naturalization by the International Organization for Migration of the ...

in some regions.

Description

This species is a mat-forming perennial grass with

rhizome In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...

s and

stolon In biology, a stolon ( from Latin ''wikt:stolo, stolō'', genitive ''stolōnis'' – "branch"), also known as a runner, is a horizontal connection between parts of an organism. It may be part of the organism, or of its skeleton. Typically, animal ...

s. The stems can reach up to 63 centimeters long,''Digitaria didactyla''.
Grass Manual. Flora of North America. but are generally 15 to 30 centimeters, with a creeping form, extending along the ground and rooting at the stem nodes.Clayton, W. D., et al. (2006 onwards)

GrassBase - The Online World Grass Flora. Accessed 20 June 2013. The narrow leaf blades are up to 7 centimeters long, usually hairless, and green to blue-green in color. The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

has 2 to 4 thin, finger-like branches each up to 7 to 10 centimeters long. They are lined with pairs of small spikelets each under 3 millimeters long. The grass can grow into a dense, leafy stand up to 20 centimeters tall unless it is kept down, for example, with

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to free range (roam around) and consume wild vegetations in order to feed conversion ratio, convert the otherwise indigestible (by human diges ...

. This species is similar to southern crabgrass (''Digitaria ciliaris''), but with fewer, narrower inflorescence branches. It is also similar to

bermudagrass ''Cynodon dactylon'', commonly known as Bermuda grass, also known as couch grass in Australia and New Zealand, is a grass found worldwide. It is native to Europe, Africa, Australia and much of Asia. It has been introduced to the Americas. Contra ...

(''Cynodon dactylon''), but with shorter, wider leaves which are more blue in color.

Biology

This grass can tolerate many soil types, including low-nutrient and low- pH substrates, but it does best in lighter soils. It thrives in

granitic A granitoid is a broad term referring to a diverse group of coarse-grained igneous rocks that are widely distributed across the globe, covering a significant portion of the Earth's exposed surface and constituting a large part of the continental ...

sands. It is somewhat tolerant of shade and occasional flooding. It usually persists in dry conditions, but it may drop its leaves.

Frost Frost is a thin layer of ice on a solid surface, which forms from water vapor that deposits onto a freezing surface. Frost forms when the air contains more water vapor than it can normally hold at a specific temperature. The process is simila ...

shrivels the leaves. The grass is very tolerant of grazing and mowing. A rhizomatous and stoloniferous species, it spreads easily via

vegetative reproduction Vegetative reproduction (also known as vegetative propagation, vegetative multiplication or cloning) is a form of asexual reproduction occurring in plants in which a new plant grows from a fragment or cutting of the parent plant or specializ ...

. It also produces seeds, which can be spread in the dung of grazing cattle and remain viable in the soil. Though it does not necessarily require

fertilizer A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Man ...

, the grass responds well to supplemental nitrogen. Good companion plants include

legume Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consum ...

s such as three-flower beggarweed (''Desmodium triflorum''), glycines (''Glycine'' spp.), pinto peanut (''Arachis pintoi''), Australian jointvetch (''Aeschynomene falcata''), Brazilian stylo (''Stylosanthes guianensis''), lotononis (''Lotononis bainesii''), round-leaf cassia (''Chamaecrista rotundifolia''), and

white clover ''Trifolium repens'', the white clover, is a herbaceous perennial plant in the bean family Fabaceae (otherwise known as Leguminosae). It is native to Europe, including the British Isles, and central Asia and is one of the most widely cultivated ...

(''Trifolium repens''). Pathogens seen in this grass include grey mould and the digitaria striate mosaic virus, a

mastrevirus ''Mastrevirus'' is a genus of ssDNA viruses, in the family ''Geminiviridae''. Mostly monocotyledonous plants serve as natural hosts. They are vectored by planthoppers. There are 50 species in this genus. Diseases associated with this genus inclu ...

of the family

Geminiviridae ''Geminiviridae'' is a family of plant viruses that encode their genetic information on a circular genome of single-stranded (ss) DNA. The family contains 15 genera. Diseases associated with this family include: bright yellow mosaic, yellow mosa ...

which is transmitted by the

leafhopper Leafhopper is the common name for any species from the family (biology), family Cicadellidae: based on the type genus ''Cicadella''. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or ...

'' Nesoclutha pallida''.Lapierra, H. and P. A. Signoret. ''Viruses and Virus Diseases of Poaceace (Gramineae).'' Editions Quae. 2004. pg. 755.CBrunt, A. A., et al. (Eds.) (1996 onwards)
Digitaria striate mosaic monogeminivirus.
Plant Viruses Online. Version: 20 August 1996. Pests include

spider mite Spider mites are members of the family Tetranychidae, which includes about 1,200 species. They are part of the subclass Acari (mites). Spider mites generally live on the undersides of leaves of plants, where they may spin protective silk webs, a ...

s of genus '' Oligonychus''.

Uses

This species has long been used as a pasture grass for grazing

livestock Livestock are the Domestication, domesticated animals that are raised in an Agriculture, agricultural setting to provide labour and produce diversified products for consumption such as meat, Egg as food, eggs, milk, fur, leather, and wool. The t ...

. Animals find it palatable. It is also planted as a

lawn A lawn () is an area of soil-covered land planted with Poaceae, grasses and other durable plants such as clover lawn, clover which are maintained at a short height with a lawn mower (or sometimes grazing animals) and used for aesthetic an ...

and used as

golf course A golf course is the grounds on which the sport of golf is played. It consists of a series of holes, each consisting of a teeing ground, tee box, a #Fairway and rough, fairway, the #Fairway and rough, rough and other hazard (golf), hazards, and ...

turf. It is thought to be "one of the most popular lawn grasses in Queensland." It may be used as other forms of

groundcover Groundcover or ground cover is any plant that grows low over an area of ground, which protects the topsoil from erosion and drought. In a terrestrial ecosystem, the ground cover forms the layer of vegetation below the shrub layer known as the ...

. It is very good for

erosion control Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development, coast, coastal areas, Bank (geography), river banks and construction. Effective erosion controls handle surface runoff and are ...

Cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

s include 'Aussiblue' and 'Tropika', grey-green grass breeds recommended for turf use.''Digitaria didactyla'' 'Aussiblue'.
The State of Queensland. Department of Natural Resources and Mines. 2012.''Digitaria didactyla'' 'Tropika'.
The State of Queensland. Department of Natural Resources and Mines. 2012.

Swazi grass

''Digitaria swazilandensis'' (swazi grass, Swaziland fingergrass) is sometimes considered to be a

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of ''D. didactyla''.Heuzé V., Tran G., Hassoun P., 2016. Swazi grass (Digitaria swazilandensis). Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. https://www.feedipedia.org/node/454 Last updated on September 10, 2016, 0:04 Other authorities treat it as a species in its own right, but it has similar uses to ''D. didactyla''. It is coarser in texture, bulkier, and less blue in color. Its stolons are less robust but it produces less seed and spreads vegetatively more often. It is more tolerant of

soil salinity Soil salinity is the salt (chemistry), salt content in the soil; the process of increasing the salt content is known as salinization (also called salination in American and British English spelling differences, American English). Salts occur nat ...

and more resistant to diseases.

References

{{Taxonbar, from=Q13906170 didactyla Grasses of Africa Flora of Madagascar Flora of Mauritius Flora of Réunion Flora of Southern Africa Forages Lawn grasses Plants described in 1809