Several techniques come to mind...
My choice would be to plant them directly into the ground, standing straight.
If needing to keep in the pots:
You could also stick them in the ground while still in the pots, or pile sandbags under & around to support the pots.
Arrange in a triangle, all pointing outward. Support ropes running to each other so they can mutually support their neighbors.
Use wood poles or PVC pipe supports, "teepee style", (inverted "V"), much more stable than a "Y".
Sky hooks with blimps. (sorry, had to add that last one)
