Pawpaws as an orchard crop and improving wild stands

I have posted some about pawpaws (Asimina triloba) before, but I haven't said a lot about them in detail. Pawpaws grow wild throughout much of the eastern, southern, and central U.S. Efforts to improve pawpaws and develop the species into a productive, domesticated, orchard crop have been made for decades. Some efforts have been much more organized and successful than others. If you are interested in pawpaws you should check out the work going on at:

Kentucky State: https://kysu.edu/academics/cafsss/pawpaw/

Neil Peterson's: https://www.petersonpawpaws.com/

My experience with pawpaws is that, here in Missouri, you have one of two things:

1) Wild pawpaws - relatively low production, smaller fruits, sometimes have 'off' flavors, some years they make no fruit, are relatively abundant in some areas, but are relatively scarce in others, generally un-maintained and growing in wooded areas (especially in the under story with partial to heavy shade).

2) Pawpaws grown as an orchard crop - often grafted trees, usually uniformly spaced in rows, can require some level of maintenance (but often less than other fruit crops in Missouri). Almost always in full (or almost full) sunlight.

There are also combinations of these. For example, you could graft wild pawpaw trees to cultivars that produce more and larger fruit. You could also graft young wild pawpaw trees so that they will produce fruit sooner. There are obstacles to attempting to turn wild pawpaw groves into orchards, but interestingly there is a history of doing this in Missouri with other crops, notably pecans. Missouri has many wild pecan groves where other trees species have been cut over the years to encourage the pecan trees to produce more nuts, and in some of these wild pecan groves now contain trees that growers have grafted that are more productive and/or disease resistant.

There are many differences between pecan and pawpaw trees, but the premise is the same. Find areas where there are wild pawpaw trees, thin out some of the other tree species, leave the pawpaw trees, and manage them for production. The advantage to this method is basically the same as it is for creating pecan groves, you can get production faster and it is possible to keep establishment costs lower. The trade-off is you may not have an ideal site, and you may never see the maximum production potential you would see if you picked and ideal site and planted the orchard there, spaced the trees at an ideal spacing, grafted only the most productive cultivars, etc.

I have done both of these at my farm and combinations of them. I have planted organized orchards of young pawpaw trees, I have unmanaged wild pawpaw stands, and I have managed and grafted wild stands of pawpaw trees. Basically this is the same thing I have with pecans as well (although the pawpaws take up much less space than pecan trees, which is great).

Here is a video of me talking about a small area I have grafted some cultivars onto wild pawpaw rootstocks.

Short pawpaw video

There are two things that make a lot of sense to me about pawpaw cultivation.

1) Low maintenance - For a FRUIT crop in Missouri. Pawpaws are more flexible in their site requirements than many other fruits. This does not mean you will get high yields on all sites (you will not). This does not mean you won't have problems on some sites, but it does mean that you can successfully grow pawpaws in areas you would never be able to grow a peach tree for example, or a grape vine (ex. in partial shade).

2) Profitability - If you have a market to sell your pawpaws, it can be quite lucrative. If you have no market to sell your pawpaws, then they probably won't be very lucrative. This concept is not unique to pawpaws, but it means that you need to plan at least a little before you are holding the fruit in your hand wondering what to do with it. There is often not a huge supply of pawpaws available (especially fresh) so if you can get them to people who want them you have a little more flexibility in your pricing (you are more of a price maker than a price taker, which is a good situation to be in).

Since costs of production can be relatively low, and prices attained for quality fruit can be high, the POTENTIAL exists to actually see some profit.

In the future I will make another post about some pawpaw cultivars I like and why I like them. There are quite a few out there right now. I will say 'Sunflower' is one of the cultivars I really like, but a full discussion of pawpaw cultivars is a post for another day.

Orchard Groundcovers and Legumes

Orchard Groundcovers

There are a lot of different options out there for orchard ground preparation, and options for plants to establish in young and mature orchards. A lot of the information out there for establishing young pecan orchards isn't really geared towards really low input approaches.

For example, in some of my orchards (pictured below), conventional tillage before planting to 'prepare' a seedbed for ground cover establishment was not really a good option in my opinion for a few reasons:

1) Cost in terms of $$. When you start talking establishing acres of grass and legumes from bare ground seed costs start climbing quickly. 

2) Cost in terms of soil erosion. Most of the trees are on extremely erodible ground, and I know these areas have lost enough topsoil in the past that I didn't want to lose more, so very minimal soil disturbance was a MUST

3) I already had some really desirable plant species growing in some of these areas and I would rather not kill them. 

I could have went with some different approaches using herbicides. If I had wanted to use herbicides on this site, my best bet probably would have been to go from tree to tree and spray a wide circle of herbicide all around them. In my opinion spraying strips of herbicides within the entire row would not have been a good idea since some of these rows of wild pecan seedlings run downhill, so it is likely I would have suffered some erosion from that approach. Some areas are a fine silt loam and others are a sandy loam, and they have a tendency to erode the instant water moves over bare soil. So when thinking about orchard preparation in your own orchards pay attention to your unique conditions, because it is very likely some of the recommendations on 'best practices' for some locations may not work well for yours.

Working on so much highly erodible soil, I always try to prioritize protecting the soil. I can replace a lot of things, trees, others plants, etc, but I can't replace soil once it is gone. If I lose an inch of topsoil through carelessness, that is more soil than is going to be created in my entire lifetime. 

In the end, what I chose to do in terms of ground cover establishment was extremely minimal and involved no herbicide or tillage. 

So what did I end up doing in terms of orchard prep?

I thought about what I would need in the future for these trees. I wanted a ground cover that I could establish with minimal inputs (no tillage, no herbicide), and one that was going to work for me to help the trees meet the high demands for nutrients they will have in the future when they are trying to grow AND produce a nut crop. Since I knew these were two of the important things to me, I decided to look into legumes and combinations of legumes I could easily establish and that were most likely to persist (and/or set large amounts of seed) and continue to fix nitrogen into the soil for years to come. I decided to establish a mix of legumes, mostly through frost seeding (if you aren't familiar with this look it up). I bought bulk quantities of red clover, common white clover, ladino clover, and korean lespedeza and frost seeded them (after I inoculated them with the appropriate inoculant) for two winters over the entire area of the pecan orchards. The results have been excellent (see picture below). 

ABOVE: Red clover and white clover are dense, the mowing early in establishment really helped.

ABOVE: You can see the prolific flowering of white clover across this field. Two years of frost seeding different types of white clover (among others) over this areas has really paid off. White clover seed especially is incredibly cheap per lb for the amount of seed you get. It also has a very low seeding rate because there are so many seeds per lb. It is also very effective at fixing nitrogen. It was a no brainer to include it in my mixtures. Note that frost seeding with clover was incredibly inexpensive for me. My total seed costs per year average out to something like $5 or so per acre, and my labor (it took a few hours to walk the whole pecan orchard using a hand broadcast seeder, but it worked very well for the extremely low seeding rate needed for things like white clover). I do not see any way to get that amount of nitrogen on these fields more efficiently and for such a long amount of time than what these plants are doing right now.

BELOW: This is a close up of what is going on. There are a lot of other plant species that are in the orchards as well, and that is fine with me. At this stage in the orchard I am not harvesting nuts from the ground so I don't need an orchard floor that is clipped very short to facilitate nut harvest. I can let the clovers, other legumes, and native plants grow relatively tall then mow them down a few times during the year. I try to time my mowing so that I am letting some of the clover and other select species go to seed if it is a species I want to see more of.

The moist winter of 2018-2019 and moist spring of 2019, coupled with regular mowing to control some of the grasses and other plants in the orchards, have allowed large numbers of the legumes to establish rapidly and make satisfactory growth this year. I have dug some samples of these legumes to check for nodulation on their roots (an indicator of below ground nitrogen fixation) and I am finding a large percentage of them with nodules. I am also favoring various native legumes including large areas of partridge pea (see picture below, really an attractive looking plant). When I mow I leave the large areas of partridge pea standing as it flowers, and allow it to go to seed. I have dug multiple partridge pea plants and I am seeing nodulation on their roots as well.

BELOW: Partridge pea on the edge of a field

BELOW: Nodules on a white clover plant