Annual, biennial and perennial herbs explained: how long each common culinary herb lives, which are hardy in a British winter, and what that means for sowing and planting.
The short answer¶
An annual grows from seed, flowers, sets seed and dies within a single year. A biennial spends its first year making leaves and roots, flowers in its second, then dies. A perennial lives for three years or more, either dying back to the ground each winter (herbaceous perennials) or keeping a woody framework above ground (shrubs and sub-shrubs). A tender perennial would live for years in its native climate but will be killed by a British winter unless brought indoors.
The practical upshot: annuals need sowing every year (often several times a year), perennials need planting once and then some annual care, and tender perennials need a frost-free home from autumn to late spring.
Herbs by life cycle¶
| Herb | Life cycle | UK hardiness | Practical notes |
|---|---|---|---|
| basil | Tender annual | Killed by frost; sulks below about 10 °C | Sow indoors in spring; outdoors only in warm summers |
| Coriander | Hardy annual | Hardy | Bolts fast in heat; sow little and often |
| dill | Hardy annual | Hardy | Direct sow; dislikes transplanting |
| chervil | Hardy annual | Hardy | Autumn sowings stand through mild winters |
| borage | Hardy annual | Hardy | Self-seeds freely |
| Summer savory | Half-hardy annual | Not frost-hardy | Winter savory is a hardy perennial |
| shiso | Half-hardy annual | Not frost-hardy | Sow indoors in spring; may self-seed |
| parsley | Biennial | Hardy | Grow as an annual; it bolts in its second spring |
| caraway | Biennial | Hardy | Seed is harvested in the second summer |
| chives | Herbaceous perennial | Hardy | Dies back in winter, returns early spring |
| mint | Herbaceous perennial | Hardy | Invasive; grow in a container |
| oregano, marjoram | Perennial (sweet marjoram is usually grown as an annual) | Oregano hardy; sweet marjoram tender | See note below |
| French tarragon | Herbaceous perennial | Borderline; dislikes wet winters | Does not come true from seed |
| sorrel, lovage | Herbaceous perennial | Hardy | Lovage grows to 2 m |
| lemon balm | Herbaceous perennial | Hardy | Self-seeds prolifically |
| Fennel | Herbaceous perennial | Hardy | Herb fennel, not the bulb vegetable |
| thyme, sage, hyssop | Evergreen sub-shrub | Hardy if well drained | Trim after flowering |
| rosemary | Evergreen shrub | Generally hardy; can be killed in severe or wet winters | Needs sharp drainage |
| Bay | Evergreen tree | Mostly hardy; young plants and pots need shelter | Can reach many metres unpruned |
| lavender | Evergreen shrub | English lavender hardy; French and others less so | Never cut back into old wood |
| lemon verbena | Deciduous shrub | Borderline; protect or bring in | Looks dead in winter; wait for spring |
| lemongrass | Tender perennial grass | Needs above 5–10 °C | Overwinter indoors |
| Curry leaf | Tender tree | Needs frost-free, ideally above 10 °C | Houseplant in winter |
| vietnamese coriander | Tender perennial | Not frost-hardy | Easy from cuttings in water |
📌 Oregano and marjoram
Common oregano (Origanum vulgare, the native wild marjoram) is a tough hardy perennial. Sweet marjoram (Origanum majorana) is a perennial in the Mediterranean but is usually killed by a British winter, so gardeners generally treat it as a half-hardy annual. Pot marjoram (O. onites) sits in between.
Why some "annuals" die early¶
Many of the leafy annuals — coriander, dill, chervil and rocket among them — are programmed to flower as soon as days lengthen and temperatures rise. Once they bolt, the leaves turn feathery and sparse and the flavour changes. You can delay bolting by:
- sowing in spring or late summer rather than midsummer
- giving them some afternoon shade and consistent moisture
- sowing directly where they are to grow, since transplanting shock can trigger flowering
- choosing slow-bolting varieties, which seed catalogues label as such
Or embrace it: green coriander seeds, dill flowers and chervil flowers are all excellent to eat. Let a few plants go to seed and collect coriander seed and dill seed for the spice jar.
Perennials need renewing too¶
Perennials do not last for ever. Thyme, sage and lavender become woody and sparse after four or five years; chives and mint become congested and less productive in the middle of the clump. Plan to replace woody herbs from cuttings every few years and to lift and divide herbaceous perennials every two or three. See propagating herbs.
Overwintering tender perennials¶
Bring tender perennials in before the first frost, usually in October. A cool, bright, frost-free place — a porch, unheated conservatory or cool bedroom windowsill — suits lemon verbena and bay. Lemongrass, curry leaf and Vietnamese coriander want warmer conditions. Water sparingly in winter, since growth is slow and roots rot easily in cold wet compost. lemon verbena drops its leaves and looks dead; it usually is not, and resprouts in late spring. The same principle applies to chilli plants, which are perennials in their native tropics: see overwintering chillies.
Planning around life cycles¶
A good herb garden mixes the three: a permanent framework of shrubs and perennials (rosemary, thyme, sage, chives, oregano), a space kept free for sowings of annuals, and pots of tender herbs that can move indoors and out. Keep annuals out of the permanent planting so that you can dig and resow without disturbing the roots of the perennials. See planning a herb garden for layout and soil.