Anthoxanthum odoratum, Sweet Vernal-grass

Image/s
Category
Grasses and Sedges
Scientific Name
Anthoxanthum odoratum
Common Name/s
Sweet Vernal-grass
Weed Information

Threat: High threat environmental weed.

Description: Perennial tufted grass to 80cm tall. Dense, erect and narrow spike-like flower heads. Leaves and roots have a distinct sweet smell like newly mown hay.

Flowers: Flowers September to January. The flower is a dense, erect spike-like head which expands at the time of pollen release. The flower colour changes from light green to bleached copper colour with age. Produces prolific seed in late spring.

Leaves and stems: Grows in loose tufts, stems unbranched, 10–20cm long with persistent leaf sheath at base. Leaf blades are thin, flat and sparsely hairy.
The ligule, arising from where the grass leaf meets the stem, is membranous and ragged at the tip 2–6mm long.

Roots: Shallow, very fine and densely matted.

Note: Forms extensive ground cover. Highly competitive with other herbaceous plants because of its rapid growth and early flowering. This grass is favoured by mowing because the layer of cut grass provides nutrients for further grass to grow. Contains chemicals that suppress growth of other plant species. Causes hay fever in humans and can be toxic to stock if large amounts are ingested, although generally not eaten by stock or rabbits due to the bitter taste.

Similar indigenous species: When not in flower it appears similar to Weeping Grass (Microlaena stipoides).
When flowering it is similar to Reed Bent-grass (Deyeuxia quadriseta).

Control measures: Hand weeding, slashing, mowing and spot spraying

Dispersal: Animals, machinery, water, vegetative, wind.