Ferula communis aka Giant Fennel

Ferula communis, or giant fennel, belongs to the carrot family, Apiaceae. It is a large perennial with an upright form. Its native range spans the Mediterranean, Arabian Peninsula, and Tanzania. It grows on dry hills, walls, and waste ground. It also grows on limestone, where spring soils may stay damp. It is not native to Britain or Ireland.

In gardens, it reaches 8–13 feet [2.5–4 metres] tall. Its spread is about 1.6–3.3 feet [0.5–1 metre]. Plants take two to five years to reach full size. The large leaves divide into many thin segments. The plant sheds its leaves rather than keeping them year-round. Branched stems carry small yellow flowers in early summer. These flowers form many rounded umbels above the leaves. Plants may die once they have set seed.

Give giant fennel full sun and a sheltered site. It needs fertile soil that drains well. Chalk, loam, and sand all suit it. It accepts acid, neutral, and alkaline soil. The RHS rates its UK hardiness as H3. This suits coastal districts and other mild parts of Britain. PFAF lists USDA zones 7–10. The RHS advises a dry bracken mulch for winter protection. Sow ripe seed in pots in a cold frame. Move seedlings into deep pots so their tap roots can develop.

Its height and leaf shape give borders a strong outline. The RHS suggests it for informal gardens and wildlife gardens. It also suits beds with a Mediterranean style. Remove flower stems early when foliage is the main aim. Otherwise, cut them after bloom unless you need seed. Aphids and slugs may attack the plant. The RHS reports few disease problems. These pests remain worth checking for as new growth develops.

PFAF records leaves as edible but gives no preparation details. Its low food-use rating offers little basis for kitchen use. The same source lists no known hazards. That statement alone does not establish that eating it is safe. PFAF also reports a gum obtained by cutting the root. People have used this gum as incense and in medicine. The account gives no details about its medical effects. Other recorded uses include stems for making furniture. Dried stem pith serves as tinder and burns slowly within the stem.