Bougainvillea wants sun and a warm location, and now is the time to plant it. One thinks of bougainvillea as being magenta with vigorous vines, but look for crimson, white, gold, orange, pink or mixed colors--some with vines that aren't quite so vigorous. Once established it is very undemanding about the amount of water and fertilizer it gets. In fact, too much of either will force it into growth at the expense of bloom. Bougainvillea seems to be in bloom so long because what we think of as flowers are really bracts that surround the much smaller flowers in the center.
Agapanthus blooms best when root-bound. In the ground, it seldom requires separating, but if you want to increase your stock, as soon as flowers finish blooming, dig up the plants and split them apart with a sharp spade.
Certain bedding begonias, the ones with brown leaves and pink, white or red flowers, can be grown in full sun. Most are dwarf and bloom better than the kinds grown in shade. In fact, they need at least half a day of sun to keep their leaf color. In shade, the foliage turns bronze and later becomes green. Now is an excellent time to plant.