It's....Pawpaw Time!

 

If my reader recalls, I have a thing for pawpaws, ever since discovering them while walking down by the James River...and reading about them, most notably Andrew Moore's book pictured below (a riveting read for us garden nerds):

The pawpaw, and in this case I mean Asimina triloba, not the other 10 species of Asimina, is North America's largest native fruit.  It is the northern most member of a family of tropical plants. The pawpaw is now in commercial cultivation, and many improved hybrids exist.  Fruit from wild trees can have variable taste depending on the tree (and by tree, I mean all the many trees that come from the same rootstock, spread by runners/vegetative growth).  The pawpaw fruit is exceedingly fragile; when ripe it is very soft and does not transport well (and they will not ripen up if picked unripe). You will not find them at your local grocery store, but may find some at a local farmer's market. The best way to have pawpaws is to grow them yourself.  The  flavor of pawpaws is often described as a combination of banana with mango and pineapple overtones.

I lucked out, I grew my pawpaws from seed collected from wild plants-talk about a wild card! Even if you taste the fruit, the flower was most likely pollinated by a genetically different tree, and you don't know what you might get from that cross. Pawpaws are seldom self fertile, as the female and male parts of the flower come out at different times.  I hand pollinate mine with male flowers collected locally.

An added bonus of growing pawpaws is that they are the host plant for the larva of the zebra swallowtail butterfly! 

The top photo shows the fruit, pulp, and the large seeds (do no eat the seeds or skin, they can make you sick,  And, like everything, some people are allergic to pawpaws).  The second photo is of pawpaw pudding, a traditional recipe, sort of a dense cake.  Some people claim that cooked pawpaw can cause digestive upset, but it never has for me, nor can I find good evidence for that claim.

For Virginia growers, Edible Landscaping in Afton, VA offers several named varieties of pawpaws.

SO DARN PROUD OF MYSELF

 

OK, these are not just photos of a spindly tree.  Well, ok, they are, but it is a special, spindly tree!  Maybe 8 years ago, I found a wild pawpaw tree that had good tasting fruit (pawpaw fruit flavor from wild trees can vary quite a bit).  I collected a few fruit, saved the seeds, cold treated them (stratified them), and raised a few trees. Last year was the first year I cross-pollinated with fruit with pollen from an unrelated tree and got a nice crop! And the fruit was just lovely, tasted great!

This year I was more careful about selecting only male flowers shedding pollen to cross pollinate my flowers.  Pawpaw flowers are considered "perfect," with both male and female parts, but also "protogynaus," or 'female first'. That is, the female part of the flower matures first, then is no longer receptive when the male part appears. This is thought to be a strategy to reduce self- pollination and increase genetic diversity, but it is one reason the pawpaw is poor at producing fruit (other reasons: their pollinators, flies and carrion beetles, are inefficient; the trees are more likely to reproduce by underground runners than sexually and: as the colony grows, the trees get shaded and flower less).  I had to make sure I had receptive female flowers, then find trees that had advanced to having male flowers, aka pollen (luckily I had scoped this out last year).

If you look at the photos above, you will see the baby pawpaw fruits circled in red (the largest cluster has 7 fruits!). It is hard to take a photos of these tiny things. I was very successful in cross-pollinating with a paint brush this year, so successful, I may have to remove some fruit as it might weight the branches down too much!

You do not have to do what I did to get  pawpaw trees, you can purchase named varieties, just make sure to get two different cultivars for cross pollination.  I just liked the challenge and adventure of doing this myself!

Pawpaws...and a new botanical term

 

                                                                         Pawpaws

I am often surprised when my gardening and hiking friends have never heard of the pawpaw, Asimina triloba. The pawpaw is North America's largest native fruit!  It generally grows by rivers, but is also being hybridized and marketed as various varieties (e.g Shenandoah, Susquehanah).  There are a few reasons my friends might not have not heard of this fruit. First, my friends might live outside its range:

Elbert L. Little, Jr., of the U.S. Department of Agriculture, Forest Service, and others - USGS Geosciences and Environmental Change Science Center: Digital Representations of Tree Species Range Maps from "Atlas of United States Trees" by Elbert L. Little, Jr.

Second, they might not hike in the correct ecosystems (rivers). Third, the pawpaw is very fragile and is not suitable for commercial production (yet), though breeding programs might take care of this in the future... but you still can't buy it in a grocery store.

There are a few other strikes against the pawpaw. It has quite a few large seeds (see photo below). It sends up suckers readily (vegetative reproduction). The wild pawpaw produces a little fruit, because its flowers are poor at getting fertilized. It is also not self-fertile. Wild fruit can vary in flavor, with the best fruit tasting a bit like banana, mango, and maybe a tad bit of pineapple. [Side note: Spanish colonizers mistook the pawpaw for papaya,and the name evolved to pawpaw]. This is where breeders have stepped up, creating hybrids with: larger, more consistent fruit; smaller and fewer seeds; better fertilization and; greater hardiness away from river environments and in more northerly climates.

I grow wild pawpaw trees that I started from the wild seed of a tasty fruit. Because my trees are from the same individual (remember they are not self-fertile), I have started hand pollinating them in spring from a few wild pawpaw flowers from another individual [sorry for all these digressions, but it can be hard to determine if you are collecting from different individuals unless they are quite a bit away from each other. Due to reproduction by suckering, a single genetic pawpaw can appear as a string of trees a quarter of a mile or more along a riverbank].

Let me share exactly why I have been really lucky in hand pollinating, and introduce a new botanical term, trioecious. You know that plant reproduction can be complicated, right? Bear with me. Plants can have flowers of only one sex, male or female (monecious). This means a single individual can be male, or female, but not both. Plants can have flowers of both sexes on one plant, male flowers AND female flowers (dioecious).  A plant can have individual flowers that have the parts of both sexes (hermaphroditic), having what are called "perfect flowers."  Generally, each species is ONE way... But pawpaws are trioecious, a tree can be either all male, or all female, or a mix of both. I guess I am lucky that I started seed that resulted in all female trees or a mixture AND that I picked enough  flowers that were pollen bearing (male) for pollinating. [Note: I pick very few flowers]. You know I am going to pay close attention to this next season!

                                                Small "wild" fruit with seed exposed

But, I am still glad I took the gamble and started growing them. Pawpaws are the only host plant for the zebra swallowtail butterfly...and that's worth it right there.

So, grow two varieties of hybrid pawpaws, central Virginians!  They need adequate water when young. If they are in full sun, they will need a shade cloth for the first few years, or you can grow them in part shade.  Edible Landscaping in Afton, VA has them at: https://ediblelandscaping.com/products/trees/Pawpaws/