I purchased a mandevilla vine in the late summer. It was blooming well. I did not plant it outside as i thought it a bit late.It now has flourished and I am wondering if I should let it grow or cut it back. I have it by a large window. Last year I cut one back and had it in the garage where it wasn't really cold and it died.Does anyone know what I should do,I really would love to have one outside in the spring,I live in B.C and can overwinter geraniams outside . Thanks for any help.