Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
The first time I overheard someone talking about pawpaws, I thought they were kidding. No real fruit could be called “pawpaw”, right? It must be something from a cartoon or video game. But they weren’t kidding. Pawpaws are real and, better yet, they are a native fruit tree.
What are Pawpaws?
Pawpaws (Asimina triloba) are deciduous fruit trees that are native to the Eastern United States and Canada. “Deciduous” is just a fancy word for a plant that loses its leaves in the fall and grows new ones in the spring.
The name pawpaw derives from the Spanish word papaya which originally referred to the tropical papaya fruit trees. The fruit of the papaya and the fruit of the pawpaw look very similar. The trees are not related and the fruit tastes very different.
Native Americans cultivated pawpaws. They used both the fruit and the inner bark of the trees. They used the inner bark to make nets, ropes, mats and to string fish. George Washington and Thomas Jefferson enjoyed the fruit. Lewis and Clark ate the fruit during their journey to the West Coast.
Pawpaw trees are hardy in zones 5 – 9. They are small trees, only growing to 25 feet tall. They are understory trees, meaning they grow underneath other taller trees. When young, they require shade, but the mature trees fruit best when grown in full sun. For me, the most interesting thing about pawpaw trees is that they grow by suckering and form large colonies called clonal mats. In the wild they are most often found in moist bottomlands and floodplains.
Pawpaws are deer and rabbit resistant. The bark, twigs and leaves all contain natural insecticides called acetogenins. They are rarely bothered by insects or other predators. The trees are the host plants for zebra swallowtail butterflies. Their caterpillars are immune to the acetogenins and happily munch the leaves. It is thought that this gives them immunity from predators because the acetogenins they have ingested would kill anything that ate them.
The bark of the pawpaw trees is light gray and smooth. The leaves are large, up to 12 inches long. The flowers are dark brown and smell like rotting meat. They attract and are pollinated by carrion eating flies. The flowers appear in the early spring just as the leaves are unfurling.
The fruits of the pawpaw tree are actually berries. They are quite large, up to 6 inches long and 3 inches in diameter and can weigh as much a pound. They start out green and ripen to yellow or brown in the late summer or early fall. They become so heavy that they bend the branches downwards. The interior of the fruits are a soft pulp. The taste of the pulp has variously been described as similar to cantaloupe, banana or mango.
Each fruit contains several lima bean sized seeds. In the wild, very few of the seeds ever germinate into new trees. Pawpaws rely on suckering to reproduce.
How to Grow Pawpaws
Choose a sunny spot in your yard. Pawpaws will grow in partial shade, but bear the most fruit in full sun. They prefer slightly acidic soil (pH 5.5 – 7.0) that is very rich and well-drained. They will grow in heavy clay soils but not if they are water-logged.
You may be tempted to go out into the forest and dig up a wild pawpaw to grow in your yard. This rarely works. Wild pawpaws are part of a larger, living mat of trees and do not transplant well. Most will die.
Most gardeners purchase their trees from nurseries, either as bare-root or containerized plants. Just like apples, you need to purchase a minimum of two different cultivars for pollination and fruit. Your nursery will have a selection of cultivars that are appropriate for your area. Plan on spacing them 15 feet apart.
The containerized plants will grow better for you because there is less disturbance of the roots when you plant them in your yard. Don’t expect any fruit until your tree is 6 feet tall.
How to Grow Pawpaws From Seed
Pawpaws can be grown from seed. Because the fruit matures in the fall, in nature the seeds would have to endure the cold of winter before germinating in the spring. The seeds need that period of cold and then warm temperatures to tell them when to germinate. You can mimic this with what’s called cold-stratification.
Sixty days before your last frost, wrap your seeds in moistened sphagnum moss and place them in a plastic bag in your refrigerator for at least 2 months. This mimics winter weather. Then remove the bag from your refrigerator and plant the seeds, lengthwise, in separate containers, ¾ inch deep. Place the containers in a sunny window and keep the soil moist. A heat mat set to 70⁰F will speed up germination which should occur in about 2 months.
You can transplant your seedlings outdoors when they have developed their first set of true leaves. Plant them 15 feet apart. They will need shade for the first two years of their lives because in nature the fruit would fall to the ground under mature pawpaw trees which would then shade the seedlings.
How to Harvest Pawpaws
Pawpaws ripen at the end of summer or the beginning of fall, depending on the cultivar. When fully ripe, the fruit will fall to the ground. If your tree has fruit still on the branches, it is not yet ripe. Fruit that is almost ripe can be picked from the tree and will finish ripening but if you pick it too soon, it will not finish ripening. Better to just wait until the fruit falls to the ground.
How to Store Pawpaws
Pawpaws are usually eaten freshly picked. They do not keep well. At room temperature, they will only keep a few days. They will last about a week if refrigerated. Alternatively, the fruits can be frozen, dehydrated or canned. They can also be used in jams and jellies, as well as in baked goods.
© 2020 Caren White