Lucerne
Species: Medicago sativa ssp. sativa
Family: Fabaceae (Pea family).
Common names: Lucerne, Alfalfa, Perennial lucerne, Violet-flowered lucerne.
Confused with: Seedlings of lucerne are easily confused with number of similar plants in this family. Adult plants are readily distinguished by their erect growth habit, flower colour and seed pods.
Description: Seedlings – the cotyledon leaves are oar-shaped, with a rounded end, 5 – 7 mm long and 3 – 5 mm wide.
Leaves - the true leaves are trifoliate, with 3 leaflets with lightly serrated edges. All leaflet are borne on short stalks, the stalk of the terminal leaflet is longer than the side leaflets, at about 4 mm. The leaflets are a pointed oval shape, 8 – 28 mm long and 3 – 15 mm wide. The leaves are borne on stems 20 to 40 mm long
Plants – an erect, multi-branched perennial plant with a very deep tap root. Plants develop a woody crown at ground level, with stems rising from the crown to around 1 m height.
Flowers – are purplish/mauve, with lighter strips. Flowers are a typical pea shape 12 – 15 mm long and develop in dense clusters of 20 – 30 flowers at the tips of the branches.
Seeds – form in a pod which develops in a whorl shape 5 – 9 mm across with 2 to 4 loose coils. Pods are initially green, but become brown and tough as they mature. The seeds are a typical bean shape, light- to mid-brown in colour, 2 – 3 mm in length, with 2 – 6 per pod.
Lifecycle/Biology: Lucerne is a perennial plant which will grow year round, but grows most actively in the warmer months. Some lucerne varieties grow more actively over winter, while others will be relatively dormant (winter active and winter dormant varieties). Plants can flower and set seed throughout the warmer months.
Ecology: Lucerne grows on most soil types, but prefers alkaline soils and doesn’t tolerate water logging.
The problem: Established and volunteer lucerne plants can be very difficult to control in fallows and following crops.
Distribution: A widely planted species, used in pastures and for hay production in much of temperate and sub-tropical Australia. Lucerne strips have been used in conjunction with cotton production on some properties. Established plants can be very difficult to remove after the lucerne phase is completed and volunteer seedlings can be problematic in crops and fallows. The plant is not highly competitive, but develops a very deep tap-root which allows it to continue to grow through dry conditions.
Origin: Introduced from the Mediterranean region.
References:
Plants of Western New South Wales, p. 404.
Compiled by:
Graham Charles
