How herbs grow

There are thousands of herbs all belonging to different plant families and needing different growing conditions. The lifecycle of herbs tend to fall into four main groups:

  • Annual – grow from seed in the spring, flower produce seed and die (example is borage).
  • Biennial – grow from a seed in the first year putting on lots of growth, flower produce seed and die in their second year (example is parsley)
  • Herbaceous perennial – a plant that lives for more than two years, dies down each autumn and sprouts again in spring (example is mint)
  • Evergreen perennial – a plant that lives from year to year and keeps green throughout the winter (example is bay).

Within those groups there are tender herbs, like lemon grass, which shouldn’t fall below one degree centigrade, half hardy herbs like lemon verbena that will survive down to temperatures of minus five degrees centigrade, and hardy herbs such as sage which will be ok down to minus ten degrees centigrade.
There are a lot of very hardy herbs such as fennel which will survive in temperatures much lower than that.