Combining a tropical-tasting fruit with a tree able to withstand winter cold, pawpaw (Asimina triloba) grows in eastern U.S. forests from Michigan to the Gulf Coast. It is hardy in U.S. Department of Agriculture plant hardiness zones 5 through 8. The only temperate-area member of the custard apple family (Annonaceae), the deciduous tree is about 25 feet tall and has a pyramidal shape. Planting a pawpaw properly helps ensure it will succeed.
Although pawpaw is a forest understory tree in the wild, when cultivated it needs full-sun exposure in order to have good fruit production. Look for a planting site that doesn't get wind, which is harmful to a pawpaw's large leaves. If you will plant a seedling, locate a site for it in full sun, but protect it from full sunlight for the first two years with shade cloth or tree shelters. The best soil for pawpaw is slightly acidic, fertile, moist, deep and well-drained. Avoid planting the tree in an area with wet, heavy or alkaline soil.
Site Preparation and Timing
The chosen planting site can be prepared before you acquire a pawpaw tree. Dig up the planting area, loosening the soil and giving it a fine texture. If you want pawpaw fruit, then plan to plant two genetically different pawpaw trees for cross-pollination, spacing them within 30 feet of each other. In the western United States, soil's organic matter may be lower than optimal but amend with peat or aged compost if necessary. Add organic matter so it is up to one-half the soil's volume, and incorporate it well with the soil. Spring is the time to plant a bare-root pawpaw. A pawpaw in a container can be planted any time.
Bare-Root vs. Container Plant
A pawpaw tree's root system is not fibrous but brittle and fleshy. Handle a bare-root tree with care. Dig a hole about the same depth as the bare-root tree's root system and two to three times the diameter of the roots. Then the tree can be set in place with its roots in the center of the hole's bottom. Fill the remainder of the hole with the soil you removed to create the hole. Bare-root trees should be planted in springtime after buds start breaking open.
If your pawpaw tree is in a container, its planting hole should be about three times the width of the container and about the same depth as the container. Carefully remove the pawpaw from its container, taking care to keep the root ball intact. Place the tree so its roots are in the center of the hole's bottom, and add or remove soil to ensure the top of the root ball is level with the top of the soil surface that surrounds the hole. Fill the rest of the hole with loose soil, gently firming it around the root ball, eliminating air pockets. Pawpaws grown inside containers can be planted year-round during the growing season.
A thorough watering of the soil is essential for a newly planted pawpaw. If necessary, build a watering basin around the planting hole's edge with soil to allow water to soak into the root area. Keep the planting site's soil moist during the first year after planting, soaking the soil deeply as often as twice each week if it has a light texture and once each week for heavier soil. In spring and summer, a 4- to 6-inch-thick layer of an acidic mulch, such as pine needles, should cover the soil surface around the tree but not touch the tree's trunk. Don't allow weeds to grow near the pawpaw while the tree becomes established.