How do I propagate pawpaw?
Answer: The pawpaw grows best in areas with hot summers and cold winters (USDA Plant Hardiness Zones 5 to 8). It is hardy and relatively pest-free, and its tolerance to shade makes it suitable for intercropping with certain other trees. In addition, the pawpaw has genetic variability that can be used to improve the plant.
To propagate, separate the seeds from the fruit and store the seeds in a plastic bag with moist (not wet) peat moss or some similar medium. Never allow the seed to dry out or freeze, as either will kill the seed. The bagged seed should be held under refrigeration for three to four months to satisfy the seed’s need for a cold period. Sow seed the following spring into pots or field about an inch deep. Most pawpaw nurserymen employ deep pots to allow for important tap root development.
Compared to apples and pears, “trueness to seed parent” is high for pawpaw; that is, seedling plants are somewhat likely to resemble their female parent. In other words, seed from high-quality fruit has a moderate chance (around 50%) of producing plants that also produce high-quality (but not necessarily identical) fruit. Nevertheless, only vegetative propagation will produce trees that can be relied upon to produce the highest-quality fruit.
Vegetative propagation for pawpaws is a matter of budding or grafting. Micropropagation by tissue culture to produce hundreds or thousands of clones at a time remains a desired, but stubbornly elusive, goal for pawpaw researchers, though progress is being made (Stanica, 2016). Budding (chip only; “T” budding has proven ineffective) or grafting should be done using dormant scionwood and actively growing seedling rootstock. Dormant scionwood should be collected in mid- to late winter and held in plastic bags under refrigeration until the seedling rootstocks are showing growth and the ambient temperatures are consistently warm. Kentucky State University recommends early June for budding and grafting, the important variable here probably being temperature: it should be consistently warm to allow for adequate callus growth and subsequent knitting together of tissues from the rootstock and the scion/bud.
Ready to learn more? Check out the ATTRA publication Pawpaw – A “Tropical” Fruit for Temperate Climates, where specialist Guy Ames discusses pawpaw production in detail, including culture, harvest and postharvest handling, marketing, and more.
Stanica, Florin. 2016. Pawpaw in vitro propagation. Proceedings of the Fourth International Pawpaw Conference, Frankfort, KY.