We have never in over 10 years pruned ours but now is not a good time as the buds are there ready to flower.

If you really must prune a Crinodendron then I suppose that it should be in winter, before the sap starts rising. We have a Crinodendron of our own and have friends with the same but none of us prune them.

If you mean Crinodendron hookeranium, then I always prune this after it has flowered, as soon as the flowers fade.

Bamboo, why do you need prune it? Ours still has a good shape after many, many years.

Might be something to do with the difference in temperature and climate between where you are and where I am in London/Middx, I don't know, but we also want to restrict its size somewhat, so I prune it yearly - not a huge amount, but enough.

'K.