Sesbania Growing Guide

This was a new, and previously untried here, introduction onto the Burncoose website in 2023. We are therefore at any early stage in assessing its sustainability for growing outdoors in Cornwall. Even if it is said to be able to withstand minor frosts it is safest to regard this as a frost free greenhouse plant. S. punicea is an erect or spreading large shrub originating from Brazil and Argentina. Perhaps the closest parallel might well be Clianthus puniceus. Clianthus will grow outside in the mildest locations as wall shrubs trained up a sunny wall in a hot location, facing south. S. punicea is probably worth trying in a similar situation. Like many similar tender wall shrubs it has far more chance of survival if it lives long enough to develop a hard woody stem. Then winter dieback and a bit of pruning is not really a problem. The leaves of S. punicea are alternate and pinnate with many light green leaflets. Attractive and different in their own right but rather similar in shape to other summer flowering shrubs which produce pea flowers – Amorpha, Indigofera and Desmodium. The pea flowers on S. punicea are red-purple in attractive racemes of 3-4 inches in length and they appear in mid-summer. The hotter the summer the better they seem to flower with us. We have yet to try cuttings ourselves but, like many other genus with pea flowers, mid-late summer with semi-ripe new growth and bottom heat looks the best bet. We hope that may be easy from seed but have yet to try. (still needs images)