Many people have heard the name Pawpaw, but few could identify it and fewer have eaten it. Pawpaw, (Asimina triloba), is a common understory tree around here. It is the only member of the custard apple family adapted to temperate areas. Pawpaws can be found as far north as Ohio (it’s the state’s official native fruit), New York and southern Ontario.
Growth requirements are interesting. They must be shaded the first year or two to survive. After that they can grow in the shade as an understory tree, but if they do they seldom fruit much. When a stand of trees has been removed or thinned the fruit set is usually heavier.
Another problem can occur though. Pollination is often poor. Furthermore, even though the flowers have both male and female parts they must be cross-pollinated with another tree. Many plums are like that. When grown in an ideal environment they can be quite prolific, but most I’ve come across in the wild around here are barren.
So what do they look like? Pawpaws have rather large alternate dark green leaves with a smooth edge. They are a small tree and never get over 25 feet tall. These trees are usually the last to leaf out in the spring. They bloom from late March to early May, usually before leaves emerge. Maroon upside-down flowers are about two inches across.
Fruits ripen from late August to early October and often grow in clusters. They have large dark seeds. Individual fruits often can weight close to a pound apiece. I consider the flavor to be somewhat of a cross between banana and mango.
Pawpaws freeze well and can be eaten fresh. The flavor is much better if they are used in recipes where they are not cooked.
We’ve only begun to scratch the surface on this mystical fruit. Pawpaws helped feed the Lewis & Clark expedition on their return trip in the fall of 1810, when in western Missouri their rations ran low and game was scarce. Pawpaws are high in Vitamins A and C, very high in Potassium and Magnesium and a good source of most essential amino acids.
Pawpaw trees contain many bioactive compounds that may be either beneficial or toxic in the human diet, depending on dosage and a person’s sensitivity. Bark and seeds are high in acetogenins, chemicals poisonous to most insects and fungi attacking the plant. These chemicals also help lower the production of ATP (the energy source) in cancer cells. This reduces the growth of blood vessels that nourish these cells.
Because of this pawpaw extracts are marketed as anticarcinogens. Studies have been conducted at Purdue University for the past 30 years. According to their research Pawpaw can also reduce the side-effects of chemotherapy. Other research claims these products can kill cancer cells resistant to chemotherapy. Upjohn studies stated Pawpaw compounds were up to 300 times more potent than Taxol.
Other findings conclude pawpaw extracts to be toxic to humans. Many standardized extracts are now on the market. I suggest consulting your doctor before making any decisions.
Ted Manzer teaches agriculture at Northeastern High School.