Also called wireweed, birdstongue, cowgrass, and pigweed, knotgrass grows prostrate (low to the ground), and is very hardy and drought proof, growing even in really poor soil (though it will get much bigger in better soil). It grows with a burgundy coloured smooth stem covered by a papery sleeve that peels off at the knuckly joints. The leaves are alternate and often stalkless.

Read the article in Winter – Week 5.