Down In The Pawpaw Patch
pawpaw for commercial fruit production languished after World War II, but has continued to grow since Peterson begin his work with this plant in the l970s. Several universities have developed research programs to explore its potential. Patrick Byers of the Southwest Missouri State University Fruit Experiment Station in Mountain Grove said the commercial cultivation of pawpaws is already in progress in Missouri, with field trials beginning in 2003.
Eight cultivated varieties were selected in 2001 on the basis of fruit size, quality, rapid maturity after planting and their ability to withstand handling and to thrive in mineral, upland soil. These were grafted on rootstock from northern Arkansas in 2002 and will be transplanted to orchards in Mount Vernon and Mountain Grove in spring 2003.
Plant breeders have recently taken a renewed interest in this species not only as a fruit-producing tree, but also as an ornamental. The slender, fine-branched tree seldom grows taller than 30 feet. Its large smooth green leaves, almost a foot long, droop slightly, giving it a decidedly tropical appearance. Brown-to-maroon flowers, up to 2 inches across, appear in early spring. Besides its ornamental value, the pawpaw makes a suitable addition to butterfly gardens because it is the exclusive larval host plant of the zebra swallowtail. As a native tree, it is already adapted to our climate and soil conditions and is bothered by few pests.
For home growers, pawpaw trees are available from many conventional and native plant nurseries. Peterson recommends spring planting for container-grown stock and avoiding the use of bare root plants.
For those wishing to start their own plants, pawpaws can be grown from seeds gathered from ripened fruits. However, the flavor of the fruits may vary from the parent tree. These seeds can be overwintered in the field or cleaned and immediately refrigerated for 100 days in airtight, plastic bags with some moistened sphagnum moss to keep the seeds from dehydrating. If planted in the fall, the shoots will not appear until the following July or August, although the seed will have already sent down a 10-inch long taproot.
Cuttings from the pawpaw are difficult to root, and transplants of this tree from the wild do not do well. Young trees taken from a grove are often root suckers of a single parent tree and have very few roots of their own. Others have a long taproot, making it difficult to transplant without damage. If you attempt to transplant, do so in the spring just as the buds begin to open. Prune to bring the shoot into balance with the existing root system.
Most pawpaw trees do not self-pollinate. It is usually necessary to plant at least two trees if you want fruit. The trees should be from different groves or areas if grown from seeds or transplanted. Two different varieties are required if you use grafted trees.
Starting from seed, a pawpaw tree will normally begin flowering and fruiting in four to eight years. A grafted tree can begin flowering as early as two to three years after planting. Pawpaws do best in deep, fertile soil. It should be moist, but well drained and slightly acidic. Seedlings and grafted trees require adequate watering, fertilizing and weeding. Seedlings also require protection from full sunlight for the first few years.
As with many plants, the pawpaw tree has also been the subject of considerable research to discover uses for the numerous compounds it produces for its own defense against insects, microbes and other invasive organisms. Jerry McLaughlin, who retired from Purdue University in 1999, began studying compounds found in the bark of the pawpaw tree in 1976. His initial studies identified a number of compounds capable of controlling insects and pests, fighting tumors, and, most recently, eliminating head lice.
The pawpaw is easily overlooked among our larger or showier trees, but, like many of our native plants, its rich history and potential benefits remind us that the pawpaw still has a special place in Missouri's forests.
Pawpaw Chiffon Pie
- 1/2 cup brown sugar
- 1/2 t salt
- 2/3 cup milk
- 3 eggs, separated
- 1 cup pawpaw pulp
- 1 pkg Knox gelatin
Mix brown sugar, salt, and gelatin in a pan. Add milk and egg yolks. Cook this mixture until it comes to a boil, then stir in pawpaw pulp and refrigerate until it is chilled, around 20 to 30 minutes.
Beat egg whites, gradually adding 1/4 cup of sugar; mix until stiff peaks are made. Fold egg whites into the pawpaw blend and serve as a pie or pudding.