Growing Pawpaw

Pawpaw patch located in Schenley Park, Pittsburgh, Pennsylvania. Photo Credit: Ryan Mahony

Pawpaw for the people!

Pawpaws (Asimina triloba) are naturally an understory tree, though mature trees thrive in full sun. Relatives of the pawpaw tree such as soursop (Anonna muricata) and cherimoya (Annona cherimola) have a tropical range and are unable to grow in a colder climate. Unlike other members of its tropical family, pawpaws thrive in a temperate climate and are highly frost tolerant (1).

The history of the pawpaw tree prior to human influence dates back to the megafauna which roamed North America prior to the last ice age. These animals, such as the wooly mammoth, were the primary distributors of new pawpaw seedlings until the Quarternary extinction event (2).

Although pawpaws produce North America's largest native fruit, they are slower to reach production than traditional orchard crops. It can take 4-10 years for seedlings to produce their first fruit. Although they were enjoyed by our country's founding fathers and Native Americans for centuries prior, pawpaws have been re-discovered by the masses in recent decades. Select nurseries, orchards, universities, and very passionate individuals began to take serious interest in improving this temperate, cold hardy fruit with few natural pests or diseases.

Compared to the hundreds of years apple cultivars have had a home in nurseries, pawpaws are a new frontier for the traditional orchard model. Perhaps the most promising aspect is that many of the currently available cultivars are leaps and bounds better tasting, larger in size, and otherwise improved with respect to fruits of wild seedlings, after few generations of selective breeding and testing. The future is bright for this almost forgotten native treasure.

This website is an attempt to compile a comprehensive list of all currently available pawpaw cultivars on the market, as well as general background information for the at home pawpaw grower. I will update as newly improved fruits become available. Included are categories for taste, hardiness, relative seasonal ripeness, fruit color, and various other qualities that makes each cultivar unique or desirable.

Pawpaw Grafting

The most widely accepted way to propagate a specific cultivar is grafting. The simple description of the grafting process is cutting part of one tree and attaching it to another. Typically, in the case of pawpaws, for grafting smaller trees there is a rootstock which is a wild seedling producing lesser quality fruit, and a scion which is a branch of another cultivar (known good quality fruit). The improved cultivar will replace all future growth on the rootstock once connected by the graft. One important exception to this in the case of pawpaws is that the root systems will eventually try to grow new sprouts in the ground near the main tree which will have the same genetic material as the rootstock. This sprout can also be grafted onto or removed if not desired. This link takes you to my beginning grafting guide on www.growingfruit.org for more information.

I will also note that pawpaws seedlings remain truer to the quality of their parent fruit compared to apples and some other traditionally grown fruits. If there is open pollination of only improved varieties, it may be worth waiting to graft seedlings in case the seedling is a new improved cultivar. Top working would allow you to re-work any poor quality branches {or entire trees) in the future. The best time to graft pawpaws is after the leaves have already broken dormancy in the spring. Have fun, be SAFE, and keep a sharp knife!

Caring For Your Pawpaw

The best time of year in the Northern Hemisphere to plant any new tree is Spring. This is especially true for pawpaws which tend to break dormancy fairly late in the season compared to other trees. Because of the deep tap roots they develop, planting smaller sized trees will typically yield better long term growth. Pawpaw prefer rich soil heavy with organics (but not inundated or soggy) , similar to a temperate forest floor. There are few pests or animals that will bother an established pawpaw tree due to the high levels of acetogenins present in the tree's leaves and stems. Deer have been known to browse on ripe fallen fruit. Pawpaw trees are the main host to Zebra Swallowtail butterflies and a few other unusual insects. Similarly to how milkweed does not affect Monarch Butterflies, the Zebra Swallowtail needs Asimina Triloba to thrive. Phyllosticta is a fungus which discolors some cultivars fruit but does not affect the growth of the tree. Otherwise pawpaws are relatively disease and pest free. Fertilization is not necessary, but a nitrogen rich spring regimen may stimulate growth.