Iodanthus pinnatifidus aka Violet Rocket

Iodanthus pinnatifidus is a herbaceous perennial in the mustard family, Brassicaceae. Gardeners know it as purple rocket or false rocket. It comes from the central and eastern United States. Its native range runs from Connecticut west to Minnesota. It extends south to Alabama and Texas. Kew places it in the temperate biome. The RHS records it as non-native to Britain and Ireland.

Purple rocket grows in damp woods, moist meadows, and stream flood plains. It also occurs on slopes beside these flood plains. Garden plants usually reach 1–2 feet [0.30–0.61 metres] tall. Some reach 3 feet [0.91 metres], though this is less frequent. The listed spread reaches 2 feet [0.61 metres]. Each plant has a single stem beneath its flower clusters. That lower section of stem does not branch. Lower leaves often have pinnate lobes near their base. They bear one to four pairs of toothed lobes. A large, egg-shaped end segment completes the leaf.

The flowers bloom in May and June. They open light violet, then fade toward white. This shift gives the blooms a changing color as they age. The flowers have a scent and provide a showy display. Missouri Botanical Garden also lists the plant as attracting butterflies. The supplied sources do not describe its fruit or seeds in detail. They do note that gardeners can raise plants from seed. Plants may also spread through self-seeding in the garden.

Grow purple rocket in partial or full shade. Partial shade gives the best results, though it tolerates deep shade. It grows in average soil with moderate to high moisture. Soil rich in organic matter suits it best. Plants can withstand brief floods. These needs make it useful beside streams and in damp, shaded beds. Missouri Botanical Garden also recommends rain gardens and naturalized plantings. Its listed hardiness range covers USDA zones 4–8.

Missouri Botanical Garden describes this plant as easy to grow. It needs little upkeep when the site meets its needs. The same source reports no serious insect or disease problems. Self-seeding may help it spread within a suitable planting. The evidence does not establish that it is invasive. It gives no confirmed edible uses or toxicity findings. Do not treat that lack of information as proof of safety.