Plant the pineapple guava in well-draining soil in an area that receives full sun to partial shade. Use a garden spade to dig a hole large enough for the root ball, and deep enough to bury the plant to the same depth as it was in the nursery pot.
Water the pineapple guava if the soil becomes dry during its flowering or fruiting periods. Although this plant will tolerate dry conditions and can survive long periods without supplemental watering, low-water conditions will affect flowering and fruit production. Do not water if the soil is already moist.
Apply a layer of mulch around the base of the pineapple guava. The roots of this plant tend to grow near the surface; adding a layer of mulch will not only help protect the roots, it will help the soil retain moisture.
Feed the pineapple guava once every other month. The California Rare Fruit Growers website recommends using an 8-8-8 NPK fertilizer. Apply the fertilizer according to package directions.
Prune the tree lightly in the summer after harvesting the fruit. Use pruning shears to cut back branches to shape the tree or thin out dense interior growth. The pineapple guava does not require pruning, but a light pruning will help increase the next year's fruit production as the flowers develop on new growth. Cut back selected branches no more than half their length.
Remove the branches from the bottom 12 inches of the trunk. This helps promote growth and development of the upper part of the tree. Use pruning shears to cut the branches even with the trunk.
Harvest the fruits when they begin to drop from the tree. The fruit appears several months after flowering. Once the fruit begins to drop on its own, shake the tree's branches to cause the remaining ripened fruit to drop. Do not allow ripened fruit to remain on the ground.