Pawpaw

Asimina triloba or Pawpaw can be a rather unassuming small understory tree of rich low deciduous forests, especially near rivers or streams. They are easily recognized from above, looking down into the bottomlands by their large tropical looking leaves. The light green obovate-lanceolate leaves can reach nearly a foot in length. They are also said to contain a natural insecticide and smell like motor oil when crushed. This might explain why only Zebra swallowtail and possible two species of moth larvae eat the leaves.

This clonal tree reaches its northern limits in the lower third of the Lower Peninsula of Michigan. It is the only member of the tropical custard apple group reaching this far north. One individual can form extensive colonies by sending up root suckers from the roots. While these colonies can become rather large in area, the trees are very slow growing. Some sources list fruit production as soon as ten years from seed, but I have been watching trees for over twenty years that have yet to bloom. The largest known Pawpaw tree in Michigan is in the town of Pawpaw in VanBuren county and measures 26.5 inches in circumference or nearly eight and a half inches in diameter. There is also one in Allegan County that is at least this diameter, maybe slightly larger. They are said to be a short-live tree, but there are a few of these larger trees that must be quite old.

The smoothish dark brown bark contains the alkaloid analobine, which was once used as a medicine. The wood is light, soft, weak, course-grained, and pale yellow to lightly golden color. The inner bark was used by the Cherokees to make strong ropes and string.

The dark reddish purple to maroon flowers appear in late May to June on short pedicels along the twigs before the leaves emerge. The species epitaph “triloba” refers to the three sepals surrounding the six petals. While older sources list flies as the main pollinator, the smelly flowers are now said to be pollinated by Sap-beetles.

The pollinated flowers give way to the largest native fruit in Michigan. These round, oblong fruit can be up to five or six inches long and weigh in at nearly half a pound when mature in September to October. The edible fruit is known by many names throughout the county, but here in Michigan, most know it as Pawpaw or Custard apple. Ripe fruits turn form greenish-yellow to dark brown or black as they ripen and are high in amino acids. The fruit is usually found in cluster of two or three fruits, but this fall I found one cluster with more than 15 fruits. 2024 has been a bumper year for the fruit, with larger clusters, more fruit per tree and more trees producing than normal in west Michigan. They can be eaten raw or cooked in various ways, including a delicious bread. I like to make it with the addition of the native Shagbark hickory nuts to keep it wild. Since animals relish the tasty fruit, it is best to shake the trees to release the near ripe fruit and let them set a few to days to ripen. Some Native Americans ate the fruit raw and some made small cakes from it the were dried for latter usage.

The large brown seeds make up most of the volume of the individual fruits. The flattened dark brown seeds resemble lima bean seed in shape and appearance. The seeds contain an alkaloid known as asiminine for which the tree is named. There are stories of drying and grinding the seeds into a powder which was used to treat for head lice.

If you plant Pawpaw in the landscape, give it some room for the future as it will slowly spread. The tree is a shade tolerant understory tree that likes rich soils for best results. You will also want to acquire plants from two different counties to help ensure cross pollination as it takes two clones to pollinate. They are virtually pest and disease free. The brown hairy buds can add winter interest and the large leaves will add summer interest to your landscape. In time you may even have fruit to eat.