General Information: Pithecellobium tortum is the scientific name of the legume commonly known as Brazilian raintree. Like most of its relatives this tree has compound leaves, hard wood and is spiny.
Temperature: Will tolerate temperatures in the upper 30F range, but not for a long time.
Lighting: Although they grow in the full sun in nature, Brazilian raintrees as bonsai seem to appreciate some shade during hottest days of tropical summers.
Watering: Evenly moist.
Feeding: A regular weekly feeding program with a balanced liquid fertilizer during the growing season and once a month during cooler weather will keep the P. tortum nourished.
Pruning and Wiring: When cutting branches and twigs leave a small nub to allow for the possible die-back that often occurs. Many artists do not use a concave cutter on the Brazilian raintree for this reason. Later this can be refined. Once the initial trunk and branch shape is established, clip-and-grow is the best way to develop a Brazilian raintree.
Marcelo also stated " No wire is used here, only nylon due to the delicate green branches. It is very difficult to 'educate' the wood once it forms. It is better to use nylon strips on green branches." If you utilize wire, do so loosely or use it to tie down branches.
Propagation: Most of the styles used are upright because of the nature of the tree to grow straight when not affected by the winds in their natural habitat. Mame and shohin are excellent possibilities, especially when begun from air layers. I have seen somewhat large branches airlayered as good small trees!
Repotting: The sandy growing environment in Brazil demonstrates how well P. tortum tolerates dry conditions, however it prefers to be evenly moist in a container. By planting it in a fast draining soil this can be easily accomplished. Marcelo Miller, Rio de Janeiro wrote " when these trees are collected at seaside they are replanted in 100% pure sand (no soil)." Too much organic in the soil mix can create wet conditions which causes root rot, fungus and branch die-back