Pawpaw (Asimina triloba) produces the largest fruit of any tree native to North America, with a custard-like flesh that tastes something like a cross between banana and mango. It's a Kentucky native, growing wild in shaded creek bottoms and woodland edges across much of the eastern United States. Pawpaw suits a patient gardener: the tree itself is easy to keep alive, but it needs a second, genetically distinct tree nearby to set fruit, and it takes several years to bear. Difficulty: moderate, mostly down to pollination and the wait.
Sowing and planting
Start with a young nursery tree rather than growing from seed. Pawpaw puts down a long taproot early on, and an older bare-root tree often fails to establish because that taproot is damaged when it's dug. A containerized tree a year or two old transplants far more reliably.
Plant in spring once the soil has warmed and is workable, or in fall while the tree is dormant and the ground is still easy to dig. In zone 6b, spring planting after the last frost gives the roots the longest stretch to settle in before the first winter.
You need two genetically distinct pawpaw trees to get fruit. A single tree won't set fruit, and neither will a clump of root suckers from one parent tree, because pawpaw flowers aren't self-fertile and suckers share the same roots as — and are genetically identical to — the parent. Plant two different named varieties, or a named variety alongside a seedling from an unrelated source, within about 30 feet (9 m) of each other so pollinators can move between them.
Give young trees part shade for their first two to three growing seasons. In the wild, pawpaw starts life as understory growth, and seedlings planted straight into full sun often scorch. Shade cloth or the dappled shade of a nearby tree both work well. Once a tree has several years of growth and a full canopy, it tolerates full sun.
Growing on
Water young pawpaw trees deeply and regularly through their first two growing seasons; they don't handle drought well before the root system is established. A deep soak once a week in dry spells does more good than frequent light watering. Mature trees need less attention but still benefit from water during extended dry spells, especially as fruit is sizing up in mid to late summer.
Feed lightly. A balanced, slow-release fertilizer applied once in spring is usually enough — pawpaw isn't a heavy feeder, and pushing too much soft growth comes at the expense of fruit. A yearly layer of compost around, but not touching, the trunk feeds the tree gradually as it breaks down and helps the soil hold moisture.
Pawpaw's natural pollinators are flies and beetles, drawn in by the flowers' faint, slightly unpleasant scent, rather than bees, and they aren't always abundant or reliable enough to pollinate every flower. Hand-pollination improves fruit set: use a small, soft paintbrush to move pollen from the flowers of one tree to the open flowers of the other when the pollen looks yellow and sticky, ideally in the late afternoon. It takes only a few minutes each spring and often makes the difference between a handful of fruit and a worthwhile crop.
Harvesting
Pawpaws ripen from late summer into early autumn, depending on variety and the local season. The skin turns from green to a yellowish green, and the fruit softens to about the give of a ripe avocado; many fruits drop from the tree on their own once fully ripe. Check a fruit that's still on the tree by cupping it gently in your hand — if it yields to light pressure and comes away from the stem with a gentle twist, it's ready.
Pick fruit just before it turns fully soft if you want to ripen it a few more days on the counter, which also keeps it out of reach of wildlife, since raccoons, opossums, and squirrels all relish ripe pawpaws. Fruit that has already dropped is often ripe and ready to eat the same day — check it over for bruising first. Ripe pawpaw keeps for only a few days at room temperature and somewhat longer in the refrigerator, so plan to eat, share, or process it soon after picking.
Problems and pests
Flowers appear but little or no fruit follows
This is the most common pawpaw complaint, and it's almost always down to pollination rather than a sick tree. A single tree, or several root suckers from one parent, cannot pollinate itself. Plant a second, genetically distinct variety nearby and hand-pollinate with a small paintbrush to improve fruit set.
Flower stalks or small fruit wilt and drop
This points to pawpaw peduncle borer, a moth larva that tunnels inside the flower stalk (the peduncle) and causes the flowers or developing fruit above the tunnel to wilt and fall. Cut off and dispose of affected peduncles as you spot them, and clear fallen plant debris from around the tree over winter, where the larvae overwinter.
Leaves stripped by large green-and-black caterpillars
These are almost certainly zebra swallowtail caterpillars, which feed only on pawpaw leaves and turn into a striking native butterfly. They're generally fine to tolerate, even welcome, since pawpaw is their only host plant. Only consider stepping in if a young tree is being stripped bare and its growth is suffering.
Leaves look bleached or scorched on a young tree
This is usually sun scorch rather than disease, from planting a young tree in full sun before it's established. Move or shade the tree for its first few seasons, then let it take full sun once it has a fuller canopy.
Dark spots on leaves or fruit in a wet season
Fungal leaf spot or anthracnose can appear in humid, wet weather, showing up as dark blotches on leaves and sometimes fruit. Rake up and dispose of fallen leaves each autumn, space trees for good airflow, and water the soil rather than the foliage.
Varieties worth growing
- Sunflower — a widely planted variety valued for reliable, good-flavored fruit; a common choice for home orchards.
- Shenandoah — bred for smooth, mild-flavored flesh and good texture.
- Susquehanna — known among named pawpaw varieties for producing some of the larger fruit.
- Overleese — one of the longer-established named varieties, still popular for its flavor.
- KSU-Atwood — released from Kentucky State University's pawpaw breeding program, a leading source of US pawpaw research and new varieties.