Tanacetum parthenium aka Feverfew

Tanacetum parthenium, or feverfew, is in the aster family. This bushy perennial often lives for only a short time. It comes from southeastern Europe, Central Asia, and the western Himalayas. It has spread beyond gardens in Europe and North America. It also grows wild in parts of Chile. Garden plants grow in upright clumps with a round shape. They reach 1–3 feet [0.30–0.91 metres] tall. They spread 1–2 feet [0.30–0.61 metres] wide. RHS gives a lower top size for both height and width. It lists 1.6 feet [0.5 metres] for each.

The green leaves have a strong scent and soft feel. Their pinnate lobes give them a fern-like look. Teeth line the leaf edges. Fine hairs cover the leaves beneath. The largest leaves sit low on the stems. Leaves grow in turn on each side of the branches. The green stems stand upright and are round in cross-section. Hairs grow on their upper parts. Their lower parts are smooth. The plant sheds its leaves, rather than keeping them year-round.

Small flower heads have white rays around a yellow disc. They measure about 0.06–0.08 feet [0.019–0.025 metres] across. The heads grow in groups called corymbs above the leaves. Missouri Botanical Garden gives June to September as the bloom season. NC State gives the same months. Chicago records blooms from May through August. It also describes blooms later in the year. The central discs then form heads of dry, brown seeds. These tiny seeds have ribs and spread the plant with ease. Flowers draw bees, butterflies, and hummingbirds into the garden.

Feverfew grows best in full sun but accepts part shade. Give it light soil that drains well. Keep the soil moist, but not too wet. Sandy and loamy soils suit it across a broad pH range. It can cope with drought. But Missouri Botanical Garden says not to let soil dry out. Heavy, wet ground does not suit it. Chicago lists USDA zones 5–9; RHS rates it H6. Hot, humid summers can cause plants to decline. Use it in borders, cottage gardens, rock gardens, or pots. Use its blooms in fresh bunches or dried flower work. Remove dead flower heads to curb its strong spread by seed. Cut plants back after they bloom.

Few serious pests or diseases affect it. But spider mites can cause trouble. RHS also lists aphids and leaf-mining flies. It lists leaf and bud eelworms too. Deer tend to avoid the leaves. Sources record leaves for tea. They also record dried flowers for tea or flavouring. These uses do not mean the plant is harmless. Touching it can irritate skin. Eating it may cause mouth sores or an upset stomach. PFAF warns against use during pregnancy or with clotting problems. Feverfew has a long history as a folk remedy. Sources disagree on its proven benefits. Use it with care as a remedy.