Common Australian Garden Weeds

Digitaria didactyla

Scientific name: Digitaria didactyla Willd. Koeler


Inflorescences of blue couch (Digitaria didactyla) during anthesis showing purplish stigmas.


Prostrate habit of blue couch with distinctive bluish-green coloration of the leaves.


Close-up of digitate inflorescence of blue couch showing purple stigmas and orange anthers.

Synonyms: Panicum didactylum (Willd.) Kinth. P. sanguinale L. var. brevispicatum Maiden

Common names: Queensland blue couch, blue couch

Family: Poaceae

Origin:

Native to Mascarene Island, widespread in the tropics

Habit:

Perennial grass forming long runners, growing up 40 cm tall

Habitat:

Used as a lawn-grass in some areas, it can become a weed where there are no heavy frosts and moisture is adequate.

General description:

Stems and leaves

Plants develop long runners, with roots at the nodes. Stems are branched or unbranched. Nodes are hairless. Appendages at the base of the leaf blade (ligules) are 1 mm long and membranous, leaf sheaths have dense or sparse long hairs which sometimes are lost. Leaf blades are linear, narrowing to the tip, 1-9 x 0.1-0.3 cm. (Cultivated plants have broader leaves).

Flowers and fruit

Inflorescences are usually 2 or 3 (rarely 4) spikes 2-7 cm long, splaying apart in a finger-like fashion at the top of an erect stalk.

Distinguishing characteristics:

Perennial grass with long runners and an inflorescence with 2 or 3 spikes on an erect stalk.

Noxious status:

Not noxious.

Sources:

Kleinschmidt, H.E., Holland, A. and Simpson, P. (1996). Suburban Weeds. 3rd Edition. Department of Primary Industries, Brisbane.

Stanley, T.E. and Ross, E.M. (1983-1989). Flora of South-eastern Queensland. Volume 3. Department of Primary Industries, Brisbane.