Stetsonia coryne

Stetsonia coryne, Toothpick Cactus, is a distinctive columnar cactus from southern South America where it grows in very dry arid terrain with little rainfall. Closely related to Browningia and the Trichocereeae tribe, in the wild it forms a large shrubby arborescent shape with many branches and although relatively fast-growing it would take many years to reach such a size in cultivation where a tall modestly-branching specimen would represent an admirable addition to any collection. Its heavily-tubercled blue-green form and wooly aereoles are distinctive enough but the long chalky-brown spines are what sets this impressive cactus apart from its many columnar cousins and earn it its common name. It is the only species in its genus.

Just on the wrong side of hardy, Stetsonia coryne is cold-tolerant but not frost-hardy. It makes a perfect sculptural plant for indoors in a large pot but is not an outdoors plant - except in the summer months - for most UK locations. Experienced growers with a favoured location and a sheltered, well-drained microclimate in a xerophytic garden will be tempted to experiment with it but a very cautious approach and an ever-ready fleece is needed. A rain-shelter would be sensible.