March 28, 2014. At a large light gap left by a fallen giant and now taken over by a thick stand of pawpaws, I see their newly-opened burgundy blooms hanging down in the sunlight like lanterns. The pawpaw flower starts out as a tight bud contained by three protective, light green sepals (modified leaves) which open to reveal a flower of extra-terrestrial appearance. The six petals start out green, then turn dark burgundy or maroon. The inner row of three smaller petals produces a nectar which attracts the pollinators – carrion flies and beetles, fruit flies, blow flies, and others – which tells you something about the odor of the nectar (although I personally cannot detect much of a scent). The larger pawpaws have dozens of blooms on them, but few will actually bear fruit later this summer.
Is there a pollination issue with pawpaws? Some botanists think so. They believe that a typical patch of pawpaw trees is clonal, that is, they all originated from one tree via underground runners and are therefore all genetically identical, and that the plants cannot self-pollinate. Therefore, the insect pollinators would have to find another patch of unrelated pawpaws in order for successfully cross-pollination and fruit production. Whatever may be the case, it is obvious that nearly all of the pawpaw blooms in Congaree will never bear fruit.
I did notice a pawpaw lesson from Hurricane Hugo. Before the storm pawpaw fruit was even rarer in Congaree than it is today, but afterwards, with so many growing in full or nearly full sun, I started seeing, for the first time, a decent, at least by pawpaw standards, amount of fruit production. I attributed this to increased sunlight producing more blooms, but the reduced canopy could have also made it easier for the insect pollinators to find another patch of pawpaws to cross-pollinate.