I live in New York. Can I successfully plant bougainvillea, when is the best time to plant and where can I buy them?

gardenfanatic!
Sadly no, not in the ground. Though possibly in a container that you could bring in in the winter. Bougainvilleas (Bougainvillea)

They won't even survive my winters in NE. FL.

Someone ask me if my Orange Bougainvillea has bloomed and I have no clue which Forum it was on, so I am posting it here. Finally, this is the first blooms of 2016 on this little gem.It did not bloom all summer. The white one is still blooming from summer, but in the summer it was more on the pink side. Now it is pure white. Both were outside along with a deep red all summer.