Winter wild oat

Winter wild oat

Avena sterilis

Scientific name

Avena sterilis is a stout broad-leaved annual grass resembling cultivated oats in general appearance (Ivens, 1989).

Stem to 1.5 m height, tufted, erect, rarely geniculate, not branching, not rooting at the nodes, nodes sometimes hairy. Leaf blades 60 cm long, 6-14 mm wide, 30-40 times as long as wide, linear, not hairy. Ligule 2 mm long, membranous, truncate, sheath often on lower leaves. Inflorescence an equilateral or slightly one-sided panicle, 15-45 cm long, 8-25 cm wide. Spikelets with 2-5 florets of which only the lowest has a basal scar, pedicelled, disarticulating above the glumes, but not between the florets. Glumes equal, 30-50 mm long, 9-11 nerved. Lemmas 15-40 mm long, 7 nerved, bidentate, the uppermost awnless, the lower two with a 5-8 cm long bent and twisted dorsal awn (Hafliger and Scholz, 1981; Ivens, 1989; Stace, 1997).

The sub-species sterilis differs from sub-species ludoviciana by the larger size of some reproductive parts (spikelets with 3-5 florets; longer glume 32-45 mm; lemmas 25-33 mm; ligule greater than 5 mm) (Stace, 1997).

Propagation instructions

By seed

When the plant first emerges after the first few rains do an initial removal of this plant by holding it at the base and removing the root ball, or by inserting a weed tool at the base and popping up the root ball. If you missed any, do a follow up removal if necessary after a few weeks.

Do a second session targeting annual grasses after the last rains in late October or November to ensure no additional grasses that come up go to seed.

References and further reading

Learn more »

Wikipedia page »

Can you help us remove this species?

This species is a difficult weed in our Fynbos patches. Can you help us remove it? See our activity calendar for upcoming activities, or arrange with us visit our Fynbos patches and do the weeding in your own time.

I can help!

Important characteristics

This species was selected because it is a difficult alien invasive weed in our Fynbos patch(es).

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