The following article originally appeared in Butterfly Gardener, a NABA publication for members. It originally appeared in Vol 13: No.1, Spring 2008. NABA member Lenora Larson has graciously allowed us to reprint it here.

Host Plant: Pawpaw
By Lenora Larson

Zone envy is a common affliction among northern gardeners. My zone six heart longs for the heat of the tropical twelve so I create my “Tropics of Kansas” each summer with Cannas, Caladiums, and Castor Beans. Amazingly, there is a native Kansan that can join in the tropical romp, Asimina triloba, the Pawpaw tree. This small tree demonstrates its tropical heritage with large glossy leaves and dramatic purple flowers. Indeed, the rest of its relatives, the Annonaceae, Custard Tree family, live in the tropics. The mango-size fruits continue the tropical connection with texture reminiscent of papaya and a flavor like banana. And, Pawpaws are the obligate host of that most tropical-looking member of the swallowtail butterfly family, the elegant Zebra Swallowtail, Eurytides marcellus.

It’s a simple rule: no Pawpaws, no Zebras. I rarely see the shy, night-feeding caterpillars, but the chewed leaves and adults in mid-spring and again in July are clear proof. The butterflies are black and white vertically-striped with proportionally the longest tails of the swallowtail clan. They have a unique floating flight pattern as the males slowly glide through the garden 2 to 4 feet above the ground, intently searching for love.

If you remember the children’s song, ‘way down yonder in the Pawpaw patch’, you already know how they grow. These 10 to 15’ trees self-seed to form Pawpaw patches in the deciduous understory of bottomlands in Eastern United States.

Their wide range, extending Southern New England, across to Minnesota and south to the Gulf States and Florida, may have been helped by Native Americans, who relished the delicious fruit.

Obviously, the Pawpaw is a remarkably adaptable tree, able to withstand -20 degree winter temperatures and the humid heat of the tropics. It grows in wet river loam and clay, but can also withstand periods of drought once established. Pawpaws are a good choice for those of you infested with deer. Unlike most small trees and shrubs, they are not eaten, even by starving deer. The leaves contain highly toxic acetogenins, which deter nibbling by all critters except a leaf roller caterpillar (the only pest) and the zebra caterpillars, who embrace the toxicity to become unpalatable to birds and other predators.

If starting your own Pawpaw patch, you hope that there are other trees within Zebra flying distance. Early spring is the best time to discover if wild Pawpaws live along riverbanks and bottomlands in your area because the striking purple flowers appear before leaves emerge. They attract fly pollinators with a fetid odor, but such beauty buys forgiveness. Fall is another chance to find wild Pawpaws because the leaves turn a brilliant gold.

Trees can be purchased from nurseries or started from seed. The huge seeds should be kept moist and planted outdoors in the fall to over-winter for spring germination. Young trees will not survive direct sunlight, but an older tree can be a magnificent specimen in full-sun if 

kept well-watered. Fruit starts to form after five years, but only if you have multiple trees. Pawpaws do not self-pollinate and a near neighbor of a different cultivar produces the best fruit.

Many attempts have been made to commercialize Pawpaw’s large, tasty fruit, but they must ripen on the tree, making harvesting, shipping and storing impossible. My patch of mature Paw-Paws, started from seed twenty years ago, always hang heavy with yellow-green fruits in September. My anticipation is thwarted by Rocky Raccoon who snatches them in the night just as I am starting to think about Pawpaw custards and sorbet. Maybe this year. I’ll beat him to my taste of the tropics.