Description: A perennial species with a woody base, long narrow leaves and yellow (less commonly red or orange) flowers. A plant of southern European origin, introduced for horticulture many centuries ago and now established permanently on old mortared stone walls, such as the town walls of Carrickfergus and some of the old castle ruins about Northern Ireland. Unfortunately, cleaning and restoration of the masonry has resulted in the loss of some populations or colonies. This plant is one of a small group of species which are characteristic of ancient mortared walls; others are pellitory-of-the wall (Parietaria judaica) and snapdragon (Antirrhinum majus).

Alternative name: Cheiranthus cheiri.

All names: Erysimum cheiri (L.) Crantz; Cheiranthus cheiri L.

Distribution Map from NBN: Erysimum cheiri at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Erysimum cheiri at iNaturalist World Species Observations database.