- Snakeweeds invade disturbed areas e.g. creek lines and roadsides.
- Invades monsoon vine forests where soil has been disturbed by pigs.
- Can invade overgrazed pastures.
- Perennial shrubs to 2 m high with tough stems and a woody rootstock.
- Young stems somewhat quadrangular.
- Leaves opposite, shallow-toothed.
- Flowers with 5 petals in stiff curved spikes from the top of the branches.
1. Stachytarpheta mutabilis - Lower leaf surfaces, rachis (Main axis of flower head) and calyx hairy, flowers pink to red.
2. Stachytarpheta cayennensis - Lower leaf surfaces, rachis and calyx hairless, rachis slender, leaves membranous, flowers blue to almost white.
3. Stachytarpheta jamaicensis - Lower leaf surface, rachis and calyx hairless, rachis stout, leaves fleshy, flowers mauve, blue, violet or purple.