There are two major types of weed: annual and perennial. Annuals undergo their entire lifecycle within one year, setting seed that germinates freely. It is important to eradicate annual weeds when they are seedlings - before they have had chance to reproduce.

Perennial weeds can survive year after year, often producing deeply penetrating tap roots, rhizomes or tubers to ensure their long-term survival. Many, such as couch and bindweed, have the ability to regenerate from very small pieces of root, so it is essential that no pieces of rhizome or root are left behind when cultivating.