Iris foetidissima, the stinking iris,[1] gladdon, Gladwin iris, roast-beef plant, or stinking gladwin, is a species of flowering plant in the family Iridaceae, found in open woodland, hedgebanks and on sea-cliffs.
Its natural range is Western Europe, including England (south of Durham) and also Ireland, and from France south and east to N. Africa, Italy and Greece.[2]
It is one of two iris species native to Britain, the other being the yellow iris (Iris pseudacorus).
It has tufts of dark green leaves.[1] Its flowers are usually of a dull, leaden-blue colour, or dull buff-yellow tinged with blue. The petals have delicate veining. It blooms between June and July, but the flowers only last a day or so.[3]The green seed capsules, which remain attached to the plant throughout the winter, are 5–8 cm (2–3 in) long; and the seeds are scarlet.
It is known as "stinking" because some people find the smell of its leaves unpleasant when crushed or bruised,[1] an odour that has been described as "beefy". Its common names of 'gladdon' and 'gladwyn' or 'gladwin', are in reference to an old word for a sword, (Latin 'gladius') due to the shape of the irises leaves.[3]
This plant is cultivated in gardens in the temperate zones. Both the species[4] and its cultivar 'Variegata'[5] have gained the Royal Horticultural Society's Award of Garden Merit.[6]