Paw Paw Tree Pollination
Regarding pollination of paw paw trees, there is some controversy about whether or not they are self-pollinating. Based on that maybe 1 out of 100 to 200 flowers will produce fruit, they are considered as self-infertile, though more flowers may pollinate on trees in different areas of the country. One problem with pollination is that bees don't like and will not visit the flowers of paw paw. Instead, they rely on flies and carrion beetles for pollination, which are not abundantly indigenous throughout the US.
Some sources say that you must have two grafted varieties for pollination, but this doesn't make sense because how did trees pollinate before man came along to graft specific cultivars? Stark Bros says "You can plant two or more seedling pawpaw trees (grown from seed), which will be able to cross-pollinate one another," which makes more sense as this is how paw paw trees in the wild must've pollinated before grafting came along. And where do the grafted cultivars come from? They come from seedlings that showed unique characteristics and qualities. Our trees are grown from seedlings. That said, one can plant various varieties/cultivars for possible increased pollination and fruit yield.
Whether you have seedling-grown or grafted cultivars, one way to ensure increased pollination and fruit production is by hand-pollination. We do this with pomegranate trees and several other types of trees and plants in our own gardens and get way more fruits than if we don't hand pollinate.
How To Pollinate Paw Paw Tree Flowers By Hand
Beginning in March keep an eye on mature trees for the presence of the upside down maroon flowers. Once they start blooming they continue to do so for about six weeks or so. When inspecting trees carry a sealable plastic food bag with you.
What you want to look for is male flowers that are shedding pollen. The petals on these flowers will be fully open and you might smell a fetid odor. Pollen is ripe for gathering when the ball of anthers is brownish in color, loose and friable. Pollen grains should appear as small beige-colored particles, as shown on the tip of the paint brush in the photo below.
When you find a male flower that is shedding pollen hold your plastic bag beneath it and carefully push the bag upwards in a position where it partially envelops the flower. Then use your finger to gently tap on the base of the flower to release the pollen into the bag. Seal the bag and make sure to use the pollen within an hour.
Next, identify female flowers on the same or a different tree. Look for flowers that are no more than one-fourth to one-half open as these flowers are still in the female stage and ready to accept pollination. Mature female flowers turn from green to a maroon shade. Some green may still be present and the petals may appear to be pressed tightly together. The stigmas are a bright, shiny green. The anthers, or male parts, are immature, still green and compressed in a tight ball inside the petals at the base of the flower. As long as their petal tips have begun to crack apart, the blooms are excellent candidates for hand-pollination.
Next, dip a soft artist's paintbrush in the pollen in the bag. Spread the female flower’s petals gently with your finger. Insert the paintbrush into the flower. Touch the stigma at the base of the inside of the bloom with the pollen on the tip of the brush and remove the brush; one touch is enough. Repeated applications of pollen increases the number of seeds in the fruit that will develop from this flower.
Next, pinch off the tip of one of the petals as a reminder that you have already pollinated the flower. Skip the rest of the blooms on the branch, as developing pawpaw fruits are very heavy and can damage limbs. Repeat pollinating female flowers on other branches.
Hope this information was helpful.
Plant Long & Prosper!
Questions? | Contact Us