Decide whether to plant in the ground or in a pot. Bougainvillea thrives in places that are hot and relatively dry. If you want to keep bougainvillea outdoors all year long, it's best to be in hardiness zone 9 or higher. If you're in a colder, wetter zone, you can still grow bougainvillea if you plant it in a pot and bring it indoors for the winter. Bougainvillea do best when night temperatures don't drop below 60 °F (16 °C) and daytime temperatures don't exceed 100 °F (38 °C). Bougainvillea can be wintered over in the basement or another low light area.
Find a sunny spot in your yard. Bougainvillea is a sun-lover and it will grow best in a full sun position, in the open, facing due North (in the southern hemisphere) and due South (in the northern hemisphere). Bougainvillea needs at least six hours of full sun every day to thrive.
Choose a place with rich, well-drained soil. Bougainvillea won't do well in soil that retains too much water, so make sure the soil drains quite well. You may want to consider adding some sand, peat moss, perlite, or vermiculite to the soil. You can also plant on a slope to help promote drainage. They need rich soil that is slightly acidic, with pH between 5.5 and 6.0. Add limestone to the soil to increase the pH or sulphur to decrease the pH as necessary. If you're planting the bougainvillea in a pot, choose a soil mix with the appropriate pH level.
Plant the bougainvillea. Dig a hole as deep as the bougainvillea plant's root ball. Add a high-phosphate fertilizer to the hole to promote root growth and help the flowers bloom. Lift the bougainvillea plant from its container and tickle the roots, then wet the root ball into the hole. Lightly pat the soil around the base of the plant. If you want the bougainvillea to climb a trellis or wall, be sure to plant it near the structure. As it grows, you'll need to "train" it to climb the structure by wrapping it gently around the base. If you're planting the bougainvillea in a container, make sure to choose one with plenty of drainage holes, since bougainvillea hate to have "wet feet."