Peucedanum officinale aka Sulphurweed

Peucedanum officinale is a tall plant in the Apiaceae family. It is a perennial, so it lives for years. Gardeners know it as hog's fennel or sulphur wort. It also goes by harstrong, sulphur weed and cammock. It is native to western, central and southern Europe. The RHS lists Britain and Ireland within its native range. It grows in regions with a temperate climate. It has been found on coastal banks, in grassland and in salt marshes.

Plants form upright clumps that reach 6.6 feet [2 metres]. Their dark green leaves split into fine, grass-like parts. The leaves die back rather than stay green all year. From July through September, plants bear greenish-yellow flowers in umbels. These flower heads rise above the finely cut leaves. The flowers have little scent. In contrast, the roots have a strong sulphur smell. Plants take about two to five years to mature.

Give garden plants full sun and fertile soil. The soil should hold moisture but let excess water drain. The RHS lists chalk, clay, loam and sand as suitable. The plant also grows in acid, neutral and alkaline soils. It can grow in exposed sites or sheltered spots. The RHS gives this species an H7 hardiness rating. This covers severe continental winters below −4°F [−20°C]. Its tall form suits cottage gardens and loose, informal planting. The RHS also suggests it for wildlife gardens. PFAF lists meadows and garden beds as places to plant it.

Routine care does not call for pruning. Remove spent flower heads when you do not need seed. To grow new plants, sow seed in autumn under a cold frame. The seeds should sprout in spring. The RHS reports few usual pest or disease problems. PFAF does not flag this species as a weed. These reports do not rule out problems in every garden. When choosing a site, keep its soil needs in mind. It needs moist soil that drains well.

PFAF gives the plant an edibility score of zero. It lists no known food uses. In some people, sap contact may cause dermatitis, a skin rash. It may also make their skin more sensitive to sunlight. Skin contact is thus a concern when handling the plant. PFAF records past use as medicine, most often using the root. People used root-based remedies for coughs and chest complaints. These records do not prove that treatment works or is safe. Wounded roots can release a yellow-green fluid that dries into gum. This resin keeps the plant's strong sulphur-like smell.