Herb fennel is closely related to the vegetable Florence fennel. However, the herb is grown as a perennial, making a long-lived plant with aromatic, feathery leaves and tall heads of yellow flowers in early summer. Every part of the plant has the distinctive, aniseed-like scent and taste, and can be used in salads and cooking, particularly with fish. The flowers are attractive to a range of beneficial insects, as well as to flower arrangers.

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Fennel dislikes having its roots disturbed or being transplanted, so it is best sown where it is to grow, into pots or in the ground.

If you want to start seeds off indoors, then sow singly in modules from early spring. Transplant the young fennel plants very carefully outdoors, without disturbing the rootball. 

You can sow seeds outdoors from mid-spring, into a warm, sunny spot in light free-draining soil. Thin out seedlings as they grow, using the thinnings in salads – the final spacing should be at least 30cm (1ft) between plants. 

You can also sow into large containers filled with multi-purpose compost. When growing in containers, choose smaller varieties.



Fennel is drought tolerant once established, so shouldn’t need watering. It requires little maintenance, apart from the removal of dead stems at the end of the growing season. Fennel dies down naturally in autumn, then re-sprouts from the base in spring.

If you leave the seeds to scatter, fennel will usually self-seed readily. So remove the seedheads or faded flowers if you don’t want more plants.


Plant out bought plants in late spring and early summer. Try not to disturb the roots.

Choose a sheltered, sunny spot, and water plants well before and after planting. They make large, tall plants, so give them plenty of space, with at least 30cm (1ft) between plants.


Harvest sprigs of leaves as required from spring to autumn.

The flowers can be added to salads, and the seeds can be used fresh over the summer months or dried for later use.

To dry the seeds, cut whole seedheads in late summer when they ripen. Place in a paper bag until the seeds dry out and fall. Then store the seeds in an air-tight container. 

Recommended Varieties

Common problems


Look for colonies of greenfly on the soft shoot tips of plants or on leaves. They suck sap and excrete sticky honeydew, encouraging the growth of black sooty moulds.


Use your finger and thumb to squash aphid colonies or use biological control in the greenhouse.

Slugs and snails
Slugs and snails

These feed on the young seedlings and you'll see the tell tale slime trail on the soil around your crop, as well as on the leaves.


There are many ways to control slugs and snails, including beer traps, sawdust or eggshell barriers, copper tape and biocontrols.

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