Dwarf Granny Smith apples (Malus domestica “Granny Smith”), which develop in U.S. Department of Agriculture plant hardiness zones 5 through 9, produce green, crisp and tart fruit perfect for baking and salads. Nearly all apples (Malus spp.) Need cross-pollinating to keep fruit. Even those that are labelled as self-fruitful set bigger, better fruit when cross-pollinated.
The nearer the pollinator is to this dwarf Granny Smith, the greater the pollination. Bees and other insect pollinators will see trees near each other, resulting in the cross-pollination which will create bigger, better tasting fruit. Nearly any fertile apple tree is going to do, including the flowering crabapple (Malus spp.) , which will be hardy in USDA zones 4 through 8 and may decorate your or your neighbors’ landscapes.