Iberis amara aka Bitter Candytuft

Iberis amara is an annual in the mustard family, Brassicaceae. Gardeners know it as annual, bitter, or rocket candytuft. Kew places its native range in western Europe to northwestern Italy. It grows in temperate regions. Wild plants grow on dry, chalky hillsides and in crop fields. It has spread beyond its native range into other regions. These include India and parts of the eastern United States.

Plants grow upright, with branches near the stem tips. They can also form low, spreading mounds. Garden plants reach about 1.5 feet [0.45 metres] tall. The RHS gives an upper height and spread of 1.6 feet [0.5 metres]. Growth is fast, and plants reach full size within one year. The dark green leaves have a spoon-like or narrow shape. They grow in an alternate pattern along the stems. Lower leaves soon wither, while upper leaves lack stalks. Some leaf edges have sparse teeth and fine hairs.

Small, scented flowers open in summer, with July to August recorded. Their petals range from white to pale violet. Each flower has four petals, with two larger than the others. Groups hold 10 to 30 flowers and form rounded heads. Bees visit the blooms and pollinate them. The fruit is oval with a notch at its tip. Its seeds have narrow wings, and fruit appears in autumn.

Grow this plant in full sun and moist, well-drained soil. It accepts poor soil and needs no rich feeding ground. Chalk, loam, clay, and sand can suit it with good drainage. Neutral to alkaline soil suits it, though it tolerates mild acidity. Some shade is possible, but plants then produce fewer flowers. The RHS rates it H6; NC State lists USDA zones 6–9. Sow seed in spring or autumn. Plants need little upkeep and no pruning. Use them in beds, border edges, containers, or along paths. They also suit slopes and gardens planted for bees.

NC State reports no major plant problems. The RHS lists slugs, snails, caterpillars, and club root as possible issues. Deer and rabbits tend to leave the plants alone. It has escaped gardens but is not classed as invasive. People sometimes use the seeds to make a bitter mustard. PFAF gives it a low food-use rating and reports no known hazards. This does not establish safety for pets. Records also describe traditional use for digestive complaints and other ailments. Such records describe past use, not proof that treatments work.