Now is the best time to buy these - before they start to grow and get tangled up and are impossible to separate.

Like a shoal of tropical fish swimming among the pond weed...
A delicately built herbaceous climber, and definitely one for the greenhouse as it grows and flowers through the winter. The tubers need a dry rest in the summer.

It needs almost no heat though - just frost free is enough, and given that it's as easy as anything.
Sold out this year - sorry