Fennel

Plant Overview

Fennel (Foeniculum vulgare) is listed in the Apiaceae family and categorized as a herb with a perennial life cycle. This profile summarizes growing information for hardiness, light, soil, water, seed starting, maturity, and other available cultivation details. Difficulty is listed as Easy.

Plant ID

PLT-0052

Family

Apiaceae

Plant type

Herb

Life cycle

Perennial

Alternate names

Herb fennel, common fennel

Growth habit

Aromatic perennial forming a clump of upright stems with finely divided, feathery foliage and flat clusters of yellow flowers; readily self-sows

Mature height

Herb fennel can reach about 6.5 feet when flowering; height varies with growing conditions

Mature spread

About 18-39 inches across at maturity; allow room for the selected variety and growing conditions

Difficulty

Easy

Growing Conditions

Fennel is listed for full sun conditions. Water needs are listed as low to moderate; avoid prolonged waterlogging. The database soil reference is Well-drained soil with moderate fertility. The listed soil pH range is 6.0-7.5, and the listed hardiness range is 4-9.

Hardiness zones

4-9

Sunlight

Full sun

Soil

Well-drained soil with moderate fertility

Soil pH

6.0-7.5

Water needs

Low to moderate; avoid prolonged waterlogging

Plant spacing

Thin young plants to at least 12 inches apart; allow additional room for large established plants

Seed & Germination

For seed starting, the listed germination time is Usually about 1-2 weeks; timing varies with temperature, moisture, and seed quality and the seed depth is Sow about 1/2 inch deep. The listed time to maturity is Some herb fennel varieties are listed at about 60 days for leaf production; ripe seed requires flowering and additional maturation. Timing varies with variety and growing conditions. Use these values as general reference points and adjust for local climate, seed source, and growing conditions.

Germination

Usually about 1-2 weeks; timing varies with temperature, moisture, and seed quality

Germination temperature

Soil temperatures around 60-68 F are suitable for seed germination

Seed depth

Sow about 1/2 inch deep

Sowing method

Direct sow herb fennel outdoors after the danger of frost has passed

Start indoors

Optional; sow in individual modules in spring and keep seedlings in good light. Direct sowing avoids root disturbance

Transplanting

Harden off indoor seedlings and transplant while very young, before a long taproot develops. Keep the root ball intact, plant at the previous depth, and water in well

Harvest & Propagation

Days to maturity

Some herb fennel varieties are listed at about 60 days for leaf production; ripe seed requires flowering and additional maturation. Timing varies with variety and growing conditions

Harvest

Snip young leafy sprigs as needed during active growth. For dried culinary seeds, cut ripe seed heads and place in a paper bag until seeds dry and fall free; store fully dried seeds in an airtight container

Propagation

Propagated by seed; readily self-sows. Very young seedlings can be moved carefully, but established plants dislike root disturbance

Seed saving

Leave selected flower heads to develop seed; plants often begin flowering in their second year. Cut seed heads as they turn brown, before seeds scatter, and finish drying on trays. Collect seeds as they detach. Remove unwanted seed heads to limit self-sowing

Pollination

Predominantly cross-pollinated; isolate flowering fennel varieties when saving seed to maintain variety purity. Pollination is not required for harvesting leaves

Garden Information

Common pests

Slugs and snails can damage seedlings and fresh shoots; aphids may colonize young foliage

Common diseases

Root rot can develop in waterlogged soil; provide good drainage

Uses

Anise-flavored leaves, flowers, and seeds used in salads and cooking; also grown for ornamental foliage and flowers that attract pollinating insects