From The Garden, RHS mag, March 2003:
Plants produce long trailing or climbing stems up to 10ft with heart shaped leaves and tuberous roots.
Grow these tender perennials as annuals in the UK. Plant under glass frames, through polythene in beds to raise soil temperature, or grow in pots in an unheated glasshouse.
Were you planning one of those options, eg having black polythene on your beds to raise temperature? It sounds like a wigwam is a good idea to let them grow up rather than sprawling.