Planting full-canopied, slow-growing trees rather than tall, skinny varieties on the west side of your home will make best use of their shade in blocking searing afternoon rays. The natural forms of mesquites, palo verdes, and mallees provide this screening.
Vines on a trellis will begin shading walls the year they are planted. Even six- to eight- foot trees can shade a window the first year they are planted.
Planting a tree or large shrub that shades your air conditioner without cutting off cooling air flow can cut your bill by 10%.