Dense spikes of small four-petalled flowers in a rich deep golden-yellow over compact mounds of dark green leaves, in March, April and May.
The scent is the point. It is a heavy honey, clove and spice perfume that hangs in still spring air, and on a warm March day it carries a surprising distance. Put it beside a path or a doorway rather than at the back of a border. It matters ecologically too: wallflowers are among the first substantial nectar sources of the year, at exactly the moment queen bumblebees come out of hibernation with nothing else to feed on.
It is a biennial, so it needs sowing in summer for flowers the following spring, and nothing happens in year one. Sow a short row every year and there is always a crop coming.
Wallflowers contain cardenolides, related to the compounds in foxgloves. All parts are toxic if eaten, so keep them from children and pets, and wear gloves if your skin is sensitive.
