Petrea: Greenhouse Plants
W – warm, minimum of 13°C (55°F) / T – tropical, minimum of 18°C (65°F)
Petrea volubilis is the Purple Wreath from Mexico, Central America and the West Indies. It is a very attractive and unusual climber in that it has sprays of bright blue flowers which in Britain in warm conditions are produced from late spring. In the wild they are in flower almost continuously with two short rest periods in winter and late summer. I have to admit to never seeing this plant for sale in Britain, but I should imagine they are more available in the USA. Plants are better in tropical conditions but will still give a good display of flowers in cooler temperatures. If possible, plant them out and give them a support up which to climb. Long shoots can be cut back by a good two-thirds once flowering is over but they should then be left as flowers are formed on the previous year’s growth. It also pays to give plants a brief rest after flowering; reducing the water and stopping the feed. After a month of this they can be grown on well again.