Q.Bougainvillia
I just got a small bougainvillia from the garden center and planted it in a pot outside. Twice when I have gently lifted a vine to look at it the vine broke off. Wondering why this plant is so fragile. Is it the way I am taking care of it?

Bougainvilleas are frequently grown in pots both to restrict their size and because they grow well as a bonsai. Bougainvillea bloom best in pots when their root system is restricted so re-potting is kept to a minimum. If you do need to re-pot your bougainvillea, you should gently break the pot from around the roots if at all possible to avoid disturbance. If this is not possible, use a pallet knife to ease the roots from the sides of the pot as opposed to simply ripping the plant out.
Bougainvillea roots are also extremely sensitive to too much water. Roots that sit in water, even for a short period, often develop root or stem rot and plant death.
Bougainvillea roots require phosphorus for proper growth and development; feeding the plant a high phosphorus fertilizer will help to keep the roots as strong as possible.
https://www.gardeningknowhow.com/ornamental/vines/bougainvillea/bougainvillea-garden-care.htm