The Intriguing World of Pawpaw Flowers & Pollination
Above are photographs of this growing season’s pawpaw (Asimina triloba) flowers, which are quite interesting in the world of fruit. Some growers have told me that they smell like rotting flesh! Yes, you read that right and I don’t think most of us would know one way or the other, but because of this, beetles and flies are supposedly attracted to them and mostly do the job of their pollination. Not bees.
Without them being present, growers WORRY their pawpaw trees won't get pollinated.
Some growers even HANG RAW MEAT from their trees to attract flies. Are they nuts or is there an actual reason to do this?
I always like to do my own due diligence. The internet is littered with incorrect growing information. Especially in the world of figs and other "rare" fruits like pawpaw.
Pawpaw Blossom Scent & Purpose
What I’ve learned is that pawpaw flowers are unlike any other in the orchard. They don't produce the typical sweet, floral scent we often associate with blooming trees. Instead, they really do smell of rotting flesh. While this may not be the most pleasant of scents for humans, it has a very strategic purpose in the natural world.
This fetid odor serves as a powerful attractant for beetles and flies - the primary pollinators for Pawpaw trees. Without these insects, pawpaw trees may not pollinate effectively, leading to lower fruit yields. This concern has led some to adopt seemingly eccentric practices. Some growers do indeed hang raw meat from their pawpaw trees to attract flies.
Such measures may seem extreme, but they underline the lengths that growers will go to ensure successful pollination, which speaks to how amazing a ripe pawpaw harvested right off the tree can be. However, a closer look at the Pawpaw tree's pollination process suggests that Mother Nature often has her own solutions.
Pawpaw Companion Plants
Upon inspecting Pawpaw flowers, it's not uncommon to find various insects, including ants and common houseflies, busy at work. They naturally aid in pollination without any need for raw meat, hand pollination, or other extraordinary measures. This aligns with the expectation that nature when allowed to flourish, has a way of managing its complex systems.
To support these natural processes, creating an ecosystem beneficial for insects specific to pawpaw pollination is key. Companion plants like marigolds and Callery pears, which have similar-smelling flowers and can be grown in similar climates as the pawpaw, can be used to attract these beneficial insects. Other plants with unpleasant odors to humans like the crown imperial, corpse flower, and eastern skunk cabbage also serve a purpose, attracting pollinators or repelling predators.
Self Pollinating Pawpaw
Pawpaw trees are generally self-infertile, requiring cross-pollination from different Pawpaw tree varieties for successful fruit set. This process, while weather-dependent and complex, can be facilitated by attracting insects naturally or through manual methods.
Asimina triloba 'Sunflower' is a unique variety of Pawpaw that stands out for its partial self-fertility, a rarity among its counterparts. This hardy northern selection, originating from Kansas, boasts large and flavorful fruit that tantalizes the taste buds with a medley of mango, apricot, pineapple, banana, and vanilla flavors. As a late-ripening variety, 'Sunflower' serves as a delightful reminder of tropical summer tastes just as the weather begins to cool.
Hand-Pollinating Pawpaw Trees
Hand pollination is another feasible solution for the backyard grower. The process begins with a careful selection of flowers in the early female stage. Using a hand lens, growers need to scrutinize the stigmas of the flowers for signs of readiness. A healthy stigma should appear plump, enlarged, feathery, and possibly glistening, with no visible sign of prior pollen deposition. Once such flowers are identified, they are tagged for pollination.
The actual pollination process involves using a very soft, flexible brush to gently coat the entire stigma with pollen. This action should be done thoroughly to ensure the surface is fully coated, thus eliminating the need to exclude subsequent insect visitors.
For more on pawpaw pollination, I would highly recommend reading Neal Peterson’s work found here:
Frequently Asked Questions
Q: How long does it take for a Pawpaw tree to bear fruit?
A: On average, a Pawpaw tree will start bearing fruit between 4 to 8 years after planting, depending on the tree's growing conditions and care. It's also important to note that grafted Pawpaw trees can bear fruit earlier, as soon as 2 to 3 years after grafting, but generally, they take a longer period of time to fruit than most other species.
Q: Can you eat Pawpaw seeds?
A: No, Pawpaw seeds are not edible. They are large, dark brown to black, and contain certain alkaloids that can be potentially toxic if ingested in large quantities. Always remove the seeds before consuming the fruit.
Q: Do you need a male and female Pawpaw tree or two Pawpaw trees to get fruit?
A: Yes, you generally need two different varieties of Pawpaw trees for cross-pollination to occur and for the tree to bear fruit. Pawpaw trees are typically self-incompatible, which means a tree cannot be fertilized by its own pollen. The only exception to this is a few partially self-fertile varieties like 'Sunflower.' Even in these cases, having a second variety nearby can improve fruit set.
You’re Ready to Plant Your Own Pawpaw Tree
The world of Pawpaw pollination is as fascinating as it is complex. Despite the challenges, the intrinsic wisdom of nature often provides the best solutions. As growers, our role is to understand, assist, and marvel at these wonders of the natural world.
After examining my pawpaw flowers this year, I noticed that there were 15 ants inside one of them doing the job of pollination. Others I am happy to share had common houseflies inside them and no raw meat, hand pollination, or other captain insano measures were needed to be taken.
Watch this video if you're growing pawpaw so you can enjoy the best-tasting pawpaw possible. I share another very simple trick like this one: