Pawpaw

Pawpaw is the only member of the Annonaceae, the mostly tropical custard apple family, adapted to a temperate climate. In the wild it grows as an understory tree in light shade, which is what makes it the obvious fruit for the second storey of a food forest rather than a competitor for the canopy.

One fact governs every planting decision: pawpaw is self-incompatible. Its flowers are perfect, carrying both sexes, but they are protogynous — the stigma is receptive and then done before that same flower sheds its pollen. Two genetically distinct trees are the minimum, and a single tree, however good the cultivar, is a landscape plant rather than a crop.

The pollinators are not bees, which largely avoid the flowers. Flies and beetles do the work, which is why growers who want fruit think about carrion and rot cues near the trees rather than about forage.

Almost every named cultivar traces to one of three origins. A few are wild finds — a tree somebody noticed in Indiana or Kansas and propagated. Most of the rest come from two breeding efforts: Neal Peterson’s private programme, built from the surviving remnants of five early twentieth-century collections and named for rivers, and the public programme at Kentucky State University. The rights on those two differ, and the difference is recorded on each entry.