Common Australian Garden Weeds

Sida rhombifolia

Scientific name: Sida rhombifolia L.


Habit of a young common sida (Sida rhombifolia) plant with diamond-shaped (rhomboid) leaves.


Seedling of common sida.

Common names: Common sida, sida-retusa, paddy's lucerne

Family: Malvaceae

Origin:

Cosmopolitan species.

Habit:

Small perennial shrub with erect woody stems growing up to 60 cm tall. Forms a deep taproot.

Habitat:

A native plant but considered a widespread and common weed of untended areas.

General description:

Stems and leaves
Stems are woody with a tough bark. The leaves have stalks (petioles) 3-10 mm long. The leaves are wedge-shaped at the base with the widest part about half way along the length (ie. like a diamond), 1.5-8.5 x 0.6-4 cm. The leaf margins are toothed towards the tip and mostly entire towards the base of the blade. The leaves have small star-like (stellate) hairs on the upper and lower surfaces. The young stems are similarly hairy.
Flowers and fruit
The flowers are radially symmetrical, yellow to pale orange, 1.5-2 cm across, with five petals (7-8 mm long). Flowers are produced in the leaf axils, carried singly on thin 1-2.5 cm long stalks. The fruits are 2.5-3 mm high and 5-6 mm across, with vertical ribs forming 8-10 segments. The seeds are 2 mm long, dark brown with two ribs and two erect points. Flowering occurs from spring to autumn.

Distinguishing features:

A perennial shrub with erect stems and alternate diamond shaped leaves with toothed margins near the base. Flowers are individually stalked and have five, yellow or pale orange petals.

Noxious status:

Considered noxious in the Northern Territory.

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 2. Department of Primary Industries, Brisbane.

Anonymous. (2000). Noxious Weed List for Australian States and Territories. Prepared by the National Weeds Strategy Executive Committee.

Auld, B.A. and Medd, R.W. (1996). Weeds: An Illustrated Botanical Guide to Weeds of Australia. Inkata Press, Sydney.