Zone
  5a/4b
Pollination
  self-sterile (monoecious)
Blooms
  mid-late
(in comparison to other species)
Ripens
  4+ months
(from the start of the grow season)
Chill Hours
  400
pH
  5.6 - 7.3
Yield
  3 - 4 years (clone), 5 - 7 years ( seedling)
Tolerant
  shade

Native Range and Climate



Pawpaws (Asimina triloba) are native to the United States, east of the prairies, where the climate is generally humid subtropical (Cfa) and hot summer continental (Dfa).  Only the earliest ripening pawpaws – such as Allegheny, Summer Delight, and Pennsylvania Golden – should be attempted in the warm summer climate (Dfb) further to the north.

Within their native range, pawpaws tend to receive an average of 3" to 5" of rainfall per month throughout the year.  While they have been grown in mediterranean and semi-arid climates, they may require occasional irrigation during spring and summer if you wish to get them to fruit (or even survive).

Young trees (1 or 2 years of age) may require shade or filtered light since exposure to full sun can damage or kill them.  Mature trees prefer full sun, but they are capable of producing some fruit in heavy shade.


Flowers



Pawpaws can bloom for up to 4 weeks, but each individual flower lasts for up to 1.5 weeks.  Without hand pollination, fruit set can be low, since bees do not pollinate the flowers, flies and beetles do.  Male and female blossoms may easily overlap in the north, but I have heard of some incompatibility between earlier and later blooming trees in the south.  Unfortunately, there is very little information on varietal bloom times.

The flowers are originally female.  The petals will be partially green and burgundy in color when mature, and they will have a sticky green pistil in the center with a bright green, plastic-like appearance behind it (the stamen) that shifts to a light tan color as it ages.  This should last for at least a few days (not sure how long), but then they revert to male and start to produce pollen.  At this stage, the stamen becomes a darker tan color and fluffs up like a lion's mane around the, now obsolete, pistil.


Harvest



Harvest season can last for up to 3 weeks (depending on the variety), and different people may prefer pawpaws in different ripening stages, since it can have a fairly dramatic affect on the flavor.  For the previous two reasons, as well as the available information being quite limited, it is fairly difficult for me to give the many different varieties a proper ripening label.  Regardless, I still have enough information for it to be of some use.


Weight



Common descriptions of some pawpaw varieties often imply they produce fruit that weigh 227g to 340g or more (1 pound = 16 ounces = 454 grams), but this is somewhat misleading.  Many of these varieties typically weighed 240g or less on average (sometimes much less) based on trials held at the University of Kentucky and Missouri.  Also, the average weight of a pawpaw appears to vary greatly based on the current, or even the previous year's weather, as well as the age of the tree.  Basically, consider the average weight of pawpaws, including those I give, to be a pretty rough estimate.


Pests and Disease



There are no serious pests or disease that affect pawpaws, but out of those known to cause some damage, the pawpaw peduncle borer (Talponia plummeriana) is the most significant.  The adult moth is about 6m[1] and the larva 5mm in length.[2] Most years, they will thin out the flowers for you as they feed on them[3], but, some years, they may destroy enough to ruin the crop.[2] The larva also feeds on the roots, twigs, stems, and fruit (primarily around the seed).  Only 1-2 percent of the fruit have been observed to be affected, with no sign of it getting worse.[3] Of those that were attacked, only 1-5% of the fruit was damaged.[1]

Pawpaw scionwood with dark channels through the pith might contain pupating larva, which may help spread the moth to other locations.[3]

The asimina webworm moth (Omphalocera munroei) can be a nuisance in some locations, but they aren't a serious threat to anything other than seedlings.  Their larva primarily feed on leaves, but they may girdle stems as well.

Caterpillars of the aesthetic Zebra Swallowtail butterfly (Eurytides marcellus) feed exclusively on the leaves of species within the Asimina genus.  They may be a threat to seedlings as well, but they appear to be less of a problem than the asimina webworm moth.


Acetogenins



Acetogenins are potential neurotoxins with a possible link to atypical parkinsonism.  They are present in the entire pawpaw tree, but at a much lower rate within ripe fruit.  Some varieties – such as Potomac, Sunflower, and Wabash – have lower concentrations within their fruit as well.  There are, however, over 50 different types of acetogenins, and the first correlation made between acetogenins and those who suffered from the affliction were not eating pawpaw, they were eating soursop (a relative to pawpaw), and drinking tea made from their leaves.  Acetogenins, or at least some of them, may also have some benefits.  They were demonstrated to be pesticidal, anti-tumor, anti-malarial, anti-viral, and anti-microbial.


Family: Annonaceae



Asimina triloba (pawpaw) is the only species within the entire Annonaceae family that can be grown in some areas within the warm continental climate range (Dfb).  Almost all others are either tropical or deeply subtropical.  Some of its best known relatives are custard apple, cherimoya, soursop, and ylang-ylang, but they belong to another genus (family > genus > species).  There are quite a few other Asimina species native to southeastern United States, one of which grows as far north as Virginia (Asimina parviflora), but there doesn't appear to be much interest in them at this time.
1. The Pawpaw Peduncle Borer, Talponia plummeriana Busck (Lepidoptera: Tortricidae): A Pest of Pawpaw Fruit, .
2.
3.



Read More

Pawpaw
Asimina triloba

Allegheny

Zone
:
4b
Ripens
🍏:
early
Fruit Size
:
125g at KSU, 8% seed
Allegheny can produce an overabundance of small fruit, which can be avoided with fruit thinning. 
Thinning is unnecessary for most pawpaw varieties.

Cantaloupe

Discovered in Richmond, Kentucky.
Ripens
🍏:
mid?   :   later than Honey Dew and Marshmallow.
Seeds
:
freestone
Fruit Size
:
~300g

Davis

Selected from the wild in Michigan (1959).
Zone
:
5a
Ripens
🍏:
mid?
Fruit Size
:
up to 5" long
Two Davis pawpaw trees in Oregon, WI (Zone 5a) grew slowly for 5 years before taking off (they were reported to be over 10ft after 9 years).  It took 6 years for them to bloom.  This is substantially better than what their two Pennsylvania Golden trees had done at their test site, but it is still slower than expected.  Keep in mind, this is at only one test site in WI and the sample size was quite small.  Not much else is known about Davis, it is rarely mentioned.

Halvin

Discovered in southwestern Iowa near the city of Bedford.
Zone
:
5a
Ripens
🍏:
mid   :   2 to 3 weeks after Shenandoah
Fruit Size
:
large, 227g+
The description of one nursery claims that Halvin ripens very early, but the only report I have seen on it was quite contradicting.

Honey Dew

Discovered in Richmond, Kentucky.
Ripens
🍏:
mid?   :   somewhere between Marshmallow and Cantaloupe.
Seeds
:
freestone
Fruit Size
:
~275g

Kentucky Champion

Zone
:
5a (4b)
Blooms
💮:
  .......   :   may benefit from having another early ripening variety for pollination
Ripens
🍏:
early?

Color
:
yellow-orange flesh
Tree Size
:
grows vigorously
Fruit Size
:
large, possibly an average of 230g with 8% being seed
Yield
:
moderately productive

KSU Atwood

Originated in Maryland, introduced in Kentucky (2009).
Zone
:
5a (4b)
Ripens
🍏:
early-mid?
Fruit Size
:
120g at KSU, 8% seed
Atwood may be one of the most productive varieties.

KSU Benson

Zone
:
5a
Ripens
🍏:
early-mid?

Fruit Size
:
round-shape
Yield
:
highly productive
KSU-Benson is mentioned for being an "early season ripening variety" but it gives me no details for a proper comparison.

Mango

Selected from the wild in Tifton, Georgia (1970).
Zone
:
5a (4b)
Blooms
💮:
late
Ripens
🍏:
early-mid   :   1 to 1.5 weeks after Shenandoah
Texture
:
mushy
Mango has a mushier texture some people tend to not like, but the flavor is generally considered to be good.  It currently appears to be the fastest growing tree out of all the named varieties (Potomac and Nyomi's Delicious may rival it).  There is not much out there about the average weight of its fruit or the productivity of the tree, but based on what I have seen, I'd say that it's around 150g with at least average productivity.

Pawpaws are considered to have tropical-like flavors, with mango occasionally being one of them (according to others), but the "Mango" cultivar doesn't appear to have much of a mango flavor, if it does at all, so its name is quite deceiving.

Maria's Joy

Davis x Prolific.  Developed in Indiana.
Zone
:
5a
Fruit Size
:
large, 227g+

Marshmallow

Discovered in Richmond, Kentucky.
Ripens
🍏:
mid?   :   earlier than Cantaloupe and Honey Dew.
Seeds
:
freestone
Fruit Size
:
~250g, seeds may be around 7% of the weight.
Yield
:
highly productive
Marshmallow is the sweetest of the three freestone varieties (the others being Cantaloupe and Honey Dew).

Middletown

Selected from the wild in Middletown, Ohio (1915).
Zone
:
5a
Blooms
💮:
mid-late? (late)
Ripens
🍏:
late?

Fruit Size
:
very small, 75g at KSU
Yield
:
very low productivity

Mitchell

Selected from the wild in Jefferson County, Illinois (1979).
Zone
:
5a
Ripens
🍏:
mid-late?

Fruit Size
:
115g at KSU, 13% seed
Yield
:
very low productivity
Mitchell is one of the least productive cultivars.  The fruit weighed an average of 115g at KSU, and the seeds consisted of 13% of the weight.  In one trial, Mitchell had an average of 1.9 fruit per cluster, making it the lowest out of all 28 that were tested (the mean was 2.6 and the highest named cultivar was Wilson with 3.1 fruit per cluster).

high acetogenin content

NC-1

Davis x Overleese.  Ontario, Canada (1976).
Zone
:
5a (4b)
Ripens
🍏:
early?
Fruit Size
:
180g at KSU
NC-1 ripens during the 3rd week of September in Ontario and the 4th week of September in Northern Illinois, right next to Lake Michigan (where summers are much cooler), making it a promising cultivar for northern growers, but it is one of the less productive cultivars.

high acetogenin content

Overleese

Selected from the wild in Rushville, Indiana (1950).
Zone
:
5a
Ripens
🍏:
early-mid? (mid)

Fruit Size
:
170g at KSU
Yield
:
appears to be a light producer most years
Overleese has a milder flavor than most other pawpaws.  This attribute is often desirable since some people do not care for the strong flavor offered by the others.  It is one of the parent trees of other popular cultivars like Shenandoah and NC-1.

high acetogenin content

Pennsylvania Golden

Seed originated in Amherst, New York.
Zone
:
5a (4b)
Ripens
🍏:
early
Fruit Size
:
110g at KSU, 8% seed
Pennsylvania Golden and other early ripening varieties are recommended for cool summer climates, but, in some areas, they may not have enough time to ripen.

PA Golden appears to be one of the most productive varieties, even when considering the low weight of its fruit.  This essentially means the fruit count is very high - roughly 2 to 4 times more than the other 7 varieties tested - according to one trial.  The same trial also indicated that its pulp percentage is much lower than most of the other 7 varieties, and if correct (based on only 1 year of research), its true productivity (total flesh weight) would actually be quite average.

Fruit thinning may greatly benefit PA Golden.

Potomac

Developed in Boyce, Virginia.
Alias
:
4-2
Zone
:
5a
Ripens
🍏:
mid? (mid-late)   :   slightly later than Susquehanna?
precocious?

Fruit Size
:
235g at KSU, 4% seed
Afflictions
:
Somewhat susceptible to cracking.
Potomac is more upright, less spreading, and supposedly grows faster than most others.

low acetogenin content

Prolific

Selected (from the wild?) in Bellevue, Michigan (mid 1980's).
Zone
:
5a
Prolific currently has the worst reputation when it comes to having a bitter aftertaste (a problem that plagues some pawpaws).  The details on this are lacking, so I can't say if all of the fruit will have a bitter aftertaste or if it's a problem every year.  Alternatively, Prolific is often used as a parent tree and has helped produce a few great cultivars, such as Maria's Joy.  Overall, no one seems to recommend this cultivar, but some do imply that you should avoid it.

Rappahannock

Developed in Boyce, Virginia. Patented in 2004.
Alias
:
8-58
Zone
:
5a
Ripens
🍏:
mid

Color
:
green-yellow skin
Fruit Size
:
95g at KSU, 6% seed
Yield
:
moderately productive
Rappahannock is unique in that its leaves are held in a horizontal fashion and its fruit may display a more yellowish color when they start to ripen. 

The flavor of Rappahannock is somewhat mysterious since the cultivar isn't mentioned very often, and those that I have seen are somewhat inconsistent.  I'd say that, at worst, it has an average pawpaw flavor for an improved cultivar.

Rebecca's Gold

Originated in Bellevue, Michigan (1974).
Zone
:
5a
Ripens
🍏:
very late
Rebecca's Gold has a fairly poor reputation when it comes to flavor.  The term "watered down" is sometimes used.

Shenandoah

A seedling of Overleese.  Originated in Maryland.
Alias
:
1-7-1
Zone
:
4b
Ripens
🍏:
early-mid?   :   roughly 0 to 1.5 weeks before Overleese
precocious

Fruit Size
:
150g at KSU, 7% seed
Yield
:
above average productivity
Shenandoah is considered to have a mild flavor for a pawpaw, much like its parent "Overleese", yet it is still highly recommended.  Shenandoah is more productive than Overleese (and many other cultivars).

Summer Delight

Overleese x Sunflower?
Zone
:
5a (4b)
Ripens
🍏:
very early   :   late July to early August in Kentucky.
around 3.5 to 4 months to ripen after bloom.
Summer Delight may be the earliest ripening Pawpaw variety, but the tree may take 4-5 years to fruit.  3-4 years is about average in its native range.  Some take 6+ years in colder or drier climates.

Sunflower

Selected from the wild in Chanute, Kansas (1970).
Zone
:
5a
Ripens
🍏:
mid-late?

Fruit Size
:
155g at KSU
Yield
:
above average productivity
Sunflower is somewhat prone to having a bitter aftertaste, but it may only be detectable in some fruit and some years are better than others.  In spite of this, it is still considered to have good flavor.

Nurseries often mention Sunflower for being self-fertile, but I have not seen anyone personally confirm this, which makes me quite suspicious considering how common it is. 

low acetogenin content

Susquehanna

Developed in Boyce, Virginia. Patented 2004.
Alias
:
11-5
Zone
:
5a
Blooms
💮:
mid-late?
Ripens
🍏:
mid? (mid-late)   :   roughly 3 weeks after Shenandoah?
after Wabash

Texture
:
firmer than a ripe avocado
firmer than most, if not all, other varieties
Fruit Size
:
185g at KSU, 4% seed
Yield
:
low productivity
Susquehanna produces fairly large fruit, weighing an average of 185g at KSU, but based on other trials, they can easily be over 200 grams each.  In addition, only a small amount of its weight consists of seed (4%).  On the negative side, its overall productivity by weight may be one of the lowest.

high acetogenin content

Tropical Treat

Selected from the wild in Kentucky (2010).
Zone
:
5a
Color
:
green-yellow skin
Fruit Size
:
180g+, up to 6" long
Yield
:
productive

Wabash

Developed in Boyce, Virginia.
Alias
:
1-7-2
Zone
:
5a
Ripens
🍏:
mid   :   before Susquehanna

Color
:
yellow-orange flesh
Fruit Size
:
185g at KSU
Yield
:
above average productivity
Afflictions
:
Somewhat susceptible to cracking.
low acetogenin content

Wells

Selected from the wild in Salem, Indiana (1990).
Zone
:
5a
Blooms
💮:
mid-late? (late)
Ripens
🍏:
mid-late?

Fruit Size
:
105g at KSU, 128g elsewhere
Yield
:
very low to average productivity, possibly depending on location
low acetogenin content

Wilson

Selected from the wild in Harlan County, Kentucky (1985).
Zone
:
5a
Ripens
🍏:
mid-late?

Fruit Size
:
90g at KSU
Yield
:
moderately productive
Wilson weighed an average of 90g per fruit at KSU and is at least moderately productive.  In one trial, Wilson had and average of 3.1 fruit per cluster, making it the 2nd highest.  Out of the 28 that were tested, the mean was 2.6 fruit per cluster.  The highest was achieved by "11-13", an unreleased cultivar, with an average of 3.7 fruit per cluster.  The lowest was achieved by Mitchell and Wabash with an average of 1.9 and 2.0 fruit per cluster, respectively.

Wilson was the only cultivar to have a survival rate of 100% at the Corvallis, Oregon Regional Trials after the first 6 years had passed.  Some unknown affliction, referred to as the blue stain disease, ravaged most other grafted cultivars, killing 25% of them after 4 years and 50% after 6 years.  76 seedlings were also planted, but only 7.9% were dead after 5 years and 18.4% after 6 years.  Excluding unreleased cultivars with no commercial name (that I am aware of), Mitchell, Taylor, and Wabash (1-7-2) were the 2nd most resistant with a survival rate of 75%.  PA Golden and Rappahannock (8-58) had a survival rate of 62.5%, and NC-1, Sunflower, Susquehanna (11-5), and Potomac (4-2) had 50% remaining.  Middletown, Wells, Overleese, Taytwo, and Shenandoah (1-7-1) performed even worse.  Wilson could be used to develop resistant cultivars against the affliction, whether it is environmental or some kind of infectious disease, however, this event happened over a decade ago, and I have not heard of any significant complaints since then.  One nursery in Oregon does mention that it's likely the result of trauma or stress unrelated to micro-organisms.  Considering that the Pacific Northwest has very dry summers, and pawpaws are adapted to high rainfall, this implies that it's probably environmental.