Almond trees (Prunus dulcis) come in bitter and sweet varieties. Sweet almonds can be eaten raw or used in recipes. Bitter almonds must be processed to remove the toxic substance that causes the bitter taste, and are mostly grown commercially. Almond trees have similar care needs to peach trees and can be grown in U.S. Department of Agriculture plant hardiness zones 7 through 9. They require at least two trees be planted for proper pollination.