Iochroma grandiflorum has been flowering since Christmas and is still putting on a good display with its graceful tubular hanging bells. Its flowers are a light purple but darken towards the base and usually grow in clusters of six to eight.
The young stems and large leaves are covered in fine, glandular hairs and give the plant a rather sticky feel. The shrub is growing in the sub-tropical wing, the east wing of the Winter Garden glasshouse.
It is so rampant it has gained a height of almost 3m, reaching to the roof of the glasshouse. It regularly has to be pruned to keep it in check and stop it smothering other plants.
But the high maintenance is well worth the benefits, such as its long flowering display.
Even though it is from tropical America, this shrub will still grow well in shaded areas of the garden, but certainly isn't as vigorous outdoors.
It will flower better in warm sunny locations, and in Dunedin will need to be in a sheltered, almost frost-free position such as under trees or sheltered coastal positions.
It may drop all its leaves as the days shorten and cool, and may not flower as profusely. It can also be grown in a pot outside and moved indoors in winter months.
A well-drained loam is suitable with plenty of watering in summer and sparingly in winter.
Stephen Bishop is curator of the Winter Garden Glasshouse at Dunedin Botanic Garden.
