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Fennel

Foeniculum vulgare

Herb

Fennel is an aromatic perennial herb with feathery foliage and anise-like flavour, but it releases allelopathic compounds that inhibit the growth of most neighbouring plants. It is best grown in isolation or at the far edge of the garden.

Growing Conditions

Sunlight

Full Sun

Water Needs

Low

Soil

Well-draining, lean loam; pH 6.0–7.0

Spacing

18–24 inches; isolate from vegetable beds

Days to Maturity

Harvest fronds from year 1; seeds in 90–100 days

Growing Zones

1
2
3
4
5
6
7
8
9
10
11
12
13

Thrives in USDA Zones 4–10

Companion Planting

Good Companions

Keep Away From

When to Plant

  • Direct Sow

    After last frost; direct sow only — dislikes transplanting

  • Harvest

    Harvest fronds as needed; harvest seeds when golden brown

Organic Growing Tips

  • Grow fennel in its own dedicated bed away from vegetable gardens — its allelopathic chemicals inhibit most crops.

  • Do not plant near dill — they cross-pollinate and produce tasteless hybrids.

  • Allow fennel to flower freely; its yellow umbels are outstanding beneficial insect attractors.

  • Black swallowtail butterfly larvae feed exclusively on fennel — consider leaving a plant wild to support this species.

Common Pests

  • Aphids
  • Parsley Worm (Black Swallowtail larva)

All pest management in Garden uses safe, organic, non-toxic methods only. No synthetic pesticides, ever.