Botanical name: Stachys arvensis
Family name: Lamiaceae
Staggerweed can be easily confused with red dead-nettle (Lamium purpureum) and henbit (Lamium amplexicaule), which are also both small cropping weeds from the Lamiaceae family. All three have lilac flowers clustered at the base of leaves, and also have square stems. (From: NZ Weed Database, Massey University).