Aristolochia: Greenhouse Plants
FF – frost free only/C – cool, minimum of 7°C (45°F) / W – warm, minimum of 13°C (55°F)
These wonderful plants, mostly, go under the name of Dutchman’s Pipe—because of their strangely shaped flowers. Not what you would call a pretty flower but definitely for those who like the unusual. If only a frost free greenhouse is available the deciduous Aristolochia durior, sometimes called A. macrophylla or A. sipho, from Eastern North America can be grown. It is hardy in some areas.
This is the only one I have seen for sale as a plant. The others are obtained by seed which is best soaked for 48 hours in lukewarm water before sowing in the light at 24-26°C (75-80°F). Others need warmer conditions. A. elegans from Brazil is a good climber. The flower, 8 cm (3 in) wide, is cream blotched with maroon. A. gigantea, also from Brazil, has enormous 18-cm (7-in) blooms and the plant is far more vigorous, needing more space than A. elegans. The plants will build themselves up to flower in the summer. After flowering they are best pruned hard to keep them restricted. If A. gigantea is trained up a tall pillar or trellis, then encourage a main structure of older shoots to mature and cut the younger shoots back to within a few buds of these. Water very sparingly during winter when the plants are semi dormant. At this stage they can withstand lower temperatures. They are prone to attack from red spider mite so it pays to inspect them regularly.