Bougainvillea is a type of tropical vine, native to South America, that blooms in bright colors. Because it is hardy only to the warmer USDA zones (10a to 11) it is frequently grown in pots and brought indoors in the winter. Bougainvillea bloom better and more frequently when their roots are crowded in the pot, according to master gardeners with Travis County Master Gardeners, so re-pot your plant only when it is too large for the current container. Re-pot the bougainvillea in spring, prior to new growth.
Fill the new planting pot halfway with soil. Water the soil until it is saturated, and allow the pot to drain completely.
Remove the bougainvillea from its current pot by tipping it on its side and sliding it out. If the plant is stuck, rap sharply on the sides and bottom of the pot to loosen.
Place the bougainvillea's rootball on the soil in the new pot. Add or remove soil so that it will sit at the same depth as it did in the old pot. Backfill with soil and water until the excess water runs out of the bottom of the pot.