Planting Pawpaw Trees

Introduction

I have put together some helpful guidelines for planting and growing  pawpaw saplings based on published academic studies and 15 years of personal pawpaw growing experience in different environments. These guidelines apply to the Southeast and to other parts of the country as well.   

Sapling Selection

Container-grown saplings are far superior to bare-root saplings, which can take a whole year to recover from the transplant shock.  A 2 ft tall container-grown sapling can have fruit in 4-5 years if it is properly planted and cared for.    

Site Requirements for the Southeast and Beyond

Good site selection is the most critical requirement for pawpaw saplings.   Pawpaws are understory trees in their natural environment.  They need humidity, heat, water, and fertile moist soil to grow vigorously.  In addition sunlight is needed to produce more fruit.

I have found Central Kentucky and northeast Tennessee to have the ideal requirements.  The foothills of the Virginias, the Carolinas, and Georgia are also good, as well as the lower elevations of mountainous areas in the deep south.   

The following areas in the southeast have their challenges for various reasons:

• Mountains above 2,000 ft elevation (the heat is limited and the growing season may be too short for the late bearing pawpaw varieties)

• Piedmont (hard clay-soil combined with a soil-moisture deficit and drought) 

• Coastal Plain (extreme heat along with sandy soil that dries out quickly and has a lack of nutrients)

• Deep South (extreme heat and limited chill hours to set flower buds on the early bearing pawpaw varieties)

Climate Requirements

1) 180 or more frost-free days. (Early bearing varieties can work with less.) This seems to be more of a problem in the mountains and foothills.   Site evaluation tool  Example

2)  More than 2,500 Growing Degree Days (GDDs) [baseline 50F degrees] in a season from peak bloom season to peak fruit harvest.  (Early bearing varieties can work with less).  Assume May 1 if you don't know the peak bloom season.  

***NOTE: (Refer to the table at the bottom for a comparison of heat units required by various pawpaw varieties)

3) Five or more summer days at 90F or above.  (Early bearing varieties can work with less).

4) Sun-protection for younger trees when the temperatures go above 95F, especially over several days.  Afternoon-shade can help the trees in this situation.

5)  High summer humidity that stays consistently above 60%.  Several days of low summer humidity (like 50% or less) will cause the leaves to wilt, and the fruit to drop.  A pawpaw tree can not survive in a climate with low humidity combined with temperatures above 100F on a regular basis.   The root system is just too sparse even with regular watering.

6)  1,000 chill hours below 40F are needed to set the flower buds. (Late bearing varieties require less chill hours).

7) Winter temperatures must stay above -25F.  The southeast does not have this issue, but it is a problem for the upper Midwest, parts of New England, and Canada.

Soil and Water

1) Irrigation is strongly recommended for the first 2 to 3 years especially in the hotter dryer climates that are subject to drought conditions.

2) Fertile moist rich soil.   Clay and sandy soils should be amended with compost and mineral supplements. 

3) Close proximity to water or the water table in the ground.

4) Try to avoid frost pockets in low areas, and windy areas up on a hill.

5) Well drained soil is good, but not critical.  Pawpaws are classified as wetland understory trees.

Planting the Potted Trees

When to Plant

I prefer to plant in the fall when the sapling is starting to go dormant  -- usually around early October at my location in the mountains.  Also it works to plant in the spring after the last frost.  In the meantime I keep it watered and partly shaded in the container so it will acclimate to my climate.   

***NOTE: Do not let the root ball freeze while the container is above the ground.  It will kill the plant.  Also, before and after planting, be very careful about adding fertilizer:  when in doubt leave it out especially in the late summer when it is hot and dry.  Never fertilize in the fall.

Spacing

Pawpaw trees should generally be spaced 10 ft apart under usual circumstances, with 18 ft between rows for lawn maintenance.  Full sun is recommended for the mountains and foot hills.  In the hotter-climates of the piedmont, coastal plain, and deep south,  I recommend planting them closer-together, as close as 6 ft apart.  This will reduce sun-exposure by cross-shading the trees, and it will allow for easier soil-management with fertilizers, and better control of watering and nutrient-additions.

Digging the Hole and Planting the Sapling

Post hole diggers are the best.  Go deeper than the pot.  Put about a tablespoon of hydrogel pellets in the bottom of the hole for water-retention.  Fill the hole with soil from the ground mixed-in with the pot-soil.  The soil-line in the pot should match up to the ground-level or slightly higher.  Water the plant heavily and it should sink down in the ground a little bit.  Level it with the ground-surface.

Watering

Water the tree regularly for the first couple of years while it is growing actively.  

If the leaves are drooping then the tree needs water. 

It is hard to over-water a pawpaw tree.

Deer Protection

Deer are heavy browsers on pawpaw trees especially when they are small.  In addition the bucks will scar up the trunk on a midsized tree. I have found a wire mesh hoop about 4 ft tall -- to be very effective.  Chicken wire also works well.

Annual Care

Do not fertilize until the sapling has been in the ground at least a year. 

Beginning in the second year and thereafter:

Early February: Apply about a 1/4 cup of 10-10-10 granular fertilizer about 1 foot out from the trunk. 

Late March: Apply again.

Late winter/ early spring:  I highly recommend about a cup of Azomite around the trunk every year.

Heat Unit Requirements by Variety

The following table helps growers select varieties for their climate.  It is based on the results from a pawpaw field trial at Kentucky State University.  

Early Bearing Varieties require less GDD heat units, and they are the better choice for growers in the cooler climates of the country like the higher elevations, the Great Lakes, New England, etc.  They are also useful in the warmer climates for a longer fruit bearing season.

Late Bearing Varieties are the better choice for the deep south because the fruit will ripen and less chill hours are required to set the flower buds.  They will also work in the Midwest and Lower elevations of the Southeast.

The GDD units are baseline 50F.