Good years for Spear Grass
Good Autumn-Winter rains means it is a good year for Spear Grasses (Austrostipa spp.). Some years we are at sea in an ocean of grasses, complete with rolling waves …
Areas where the grazing pressure from kangaroos is low respond beautifully to Autumn / Winter rainfall. However, there's still only sparse cover of native grasses in areas where the grazing pressure from kangaroos is too high.
Female (left) and male (right) Red Kangaroo.
Spear Grass amongst Poached Egg Daisy (Polycalymma stuartii) September 2020
Our Spear Grasses are most Rough Spear Grass (Austrostipa scabra), Knotty Spear Grass (A. nodosa) and Balcarra Spear grass (A. nitida).
I love the Spear Grass when it is green and supple, but from November the seeds ripen. Argghhh. The awns twist into your socks, skin, the dog’s ears, and deep into the soil where they are supposed to be, waiting for the rain.
It is a cool adaptation - the seeds are self-planting. The awns (long bristly bits) are hygroscopic, meaning they absorb water. The hairs on the twisted awn base swell and shrink in response to soil moisture, and the seed is slowly twisted, head first, into the soil.
Spear Grass seed showing the long awn bristle, the twisted awn base and the pointed seed head.
Even with climate change, not every year will be a bad year. The bush, with a little help from us, can recover from climate extremes. Our average annual rainfall is 300mm and we had almost no grass at all in 2018-2019 following dismal rainfall totals of 144mm in 2018 and 175mm in 2019. 2020 was our best Spear Grass year since 2014 so was a great year to replenish the soil seed bank and collect some seeds for revegetation. As an update, 2021 was pretty good too, and 2022 was astonishing. Waist high grass everywhere!
Waist high Spear Grass in September 2022.
First published September 22, 2020. Updated 2021, 2022