Fruit Facts from
California Rare Fruit Growers, Inc.
© Copyright 1996-2001, California Rare Fruit Growers, Inc.
Pawpaw, Paw Paw, Papaw, Poor Man's Banana, Hoosier Banana, etc. (In
Australia the tropical papaya, Carica
papaya, is also known as Pawpaw).
incarna, A. longifolia, A. obovata, A. parviflora, A.
pygmaea, A. reticulata, A. tetramera, A.
X nashii. These eight
Asimina species grow in the southeastern United
Affinity: Cherimoya (Annona
cherimola), Soursop (Annona
muricata), Custard Apple (Annona reticulata),
Sugar Apple, Sweetsop (Annona
squamosa), Atemoya (Annona
squamosa X A.
The pawpaw is native to the temperate woodlands of the eastern U.S. The
American Indian is credited with spreading the pawpaw across the
eastern U.S. to eastern Kansas and Texas, and from the Great Lakes
almost to the Gulf. Fossils prove the pawpaw is indigenous to the U.S.
The pawpaw is adapted to the humid continental climate of its native
habitat. It is seldom found near the Atlantic or Gulf coasts. It
requires a minimum of 400 hours of winter chill and at least 160
frost-free days. Pawpaws appear to be sensitive to low humidities, dry
winds and cool maritime summers. It has been successfully grown in
parts of California and the Pacific Northwest that meet its growing
requirements. It has grown well in the San Jose area (USDA Climate Zone
9 or Sunset Climate Zone 15). The climatic conditions of Southern
California make growing the pawpaw there more difficult.
deep winter dormancy of the tree makes it highly frost tolerant,
withstanding temperatures of -25° F or lower (hardy to USDA Climate
Zone 5). Pawpaws can be grown as container specimens, although this is
not often practiced. A deep pot is needed to accommodate the root
The pawpaw is a deciduous, often narrowly conical tree growing from
about 12 feet to around 20 feet. Pawpaw trees are prone to producing
root suckers a few feet from the trunk. When these are permitted to
grow, the single-clone pawpaw patch comes into being. The prevailing
experiences of many individuals is that the pawpaw is a slow grower,
particularly when it is young. However, under optimal greenhouse
conditions, including photo-period extension light of approximately 16
hours, top growth of up to 5 feet can be attained in three months.
The dark green, obovate-oblong, drooping leaves grow up to 12 inches
long, giving the pawpaw an interesting tropical appearance. The leaves
turn yellow and begin to fall in mid-autumn and leaf out again in late
spring after the tree has bloomed.
Dormant, velvety, dark brown flower buds develop in the axils of the
previous years' leaves. They produce maroon, upside-down flowers up to
2 inches across. The normal bloom period consists of about 6 weeks
during March to May depending on variety, latitude and climatic
conditions. The blossom consists of 2 whorls of 3 petals each, and the
calyx has 3 sepals. Each flower contains several ovaries which explains
why a single flower can produce multiple fruits.
The pawpaw is the largest edible fruit native to America. Individual
fruits weigh 5 to 16 ounces and are 3 to 6 inches in length. The larger
sizes will appear plump, similar to the mango. The fruit usually has 10
to 14 seeds in two rows. The brownish to blackish seeds are shaped like
lima beans, with a length of 1/2 to 1-1/2 inches. Pawpaw fruits often
occur as clusters of up to nine individual fruits. The ripe fruit is
soft and thin skinned.
The young plant is very sensitive to full sunlight and requires
filtered sun for the first year or two. The use of tree shelters is an
ideal solution to the problem, permitting the plant to receive a full
day of filtered sunlight. Once established, pawpaws prefer full sun.
The large dangling leaves dislike strong winds. Overall the tree is an
excellent edible landscape addition.
Pawpaws do best in deep, fertile soil that is moist, but well-drained
and slightly acid (pH 5-7). The addition of compost to most western
soils makes them more hospitable to the pawpaw. Avoid heavy, wet,
The pawpaw needs regular watering during the growing season. The soil
should be kept moist but avoid waterlogging.
The pawpaw responds to the application of an organic or granular
fertilizer high in potassium twice a year. For container growing, 250 -
500 ppm of soluble 20-20-20 NPK plus soluble trace elements during
growth phase is optimal.
Ordinarily little pruning is required, except to remove dead, damaged
or wayward branches. Periodic pruning may be used to stimulate some new
growth each year on older trees, since it is new growth that produces
fruit the following season.
To break dormancy Pawpaw seed must receive a 90 to 120 day
stratification, i.e. exposure to cold temperatures. To accomplish this,
the seed should be placed in plastic freezer zipper bag containing a
handful of moist sphagnum moss and refrigerated at 32° - 40° F.
The over wintering of field planted seeds normally accomplishes this
Germination of pawpaw seed is
hypogeal--the shoot emerges without any cotyledons. Under ideal
greenhouse culture, germination can be expected in about seven weeks.
Seeds field-planted in the fall will emerge the following July or
But before the
shoot emerges, the seed will have sent down a 10 inch long tap root.
cuttings are essentially impossible to root, while root cuttings have
been variable to disappointing. Some success has been reported using
softwood cuttings under intermittent mist with bottom heat (80° F)
and supplemental light (14 hours). All grafting and budding techniques
can be performed on the pawpaw, but T-budding is not recommended.
Chip-budding has been reported to be successful. Scion wood should be
gathered while the tree is dormant and kept refrigerated. Grafting can
be done in the spring after vegetative growth begins.
pawpaw plants have fleshy, brittle roots with few fine root hairs,
making them difficult to transplant. It is important to follow these
Use seedlings, not root suckers.
Move the tree with roots and soil intact. A container grown specimen is
Transplant the tree in the spring after bud break.
Give the plant good drainage and keep it well watered the first year.
Pawpaw trees are relatively disease free, including a resistance to Oak
Root Fungus (Armillaria).
A number of vertebrates such as foxes,
opossums, squirrels and raccoons will eat the fruit, although deer,
goats and rabbits will not eat the leaves or twigs. The attraction of
pawpaw roots to gophers is a somewhat unknown factor, but it seems
likely that they would not be the gopher's first choice. The Zebra
Swallowtail butterfly's larvae feed exclusively on young, pawpaw
foliage, but never in great numbers. On the West Coast, slugs, snails
and earwigs can be easily controlled by the application of Tanglefoot
to a band around the pawpaw tree trunk. It is important not to apply
Tanglefoot directly to the bark, however.
Poor pollination has always plagued the pawpaw in nature, and the
problem has followed them into domestication. Pawpaw flowers are
perfect, in that they have both male and female reproduction parts, but
they are not self-pollinating. The flowers are also protogynaus, i.e.,
the female stigma matures and is no longer receptive when the male
pollen is shed. In addition pawpaws are self-incompatible, requiring
cross pollination from another unrelated pawpaw tree.
Bees show no
interest in pawpaw flowers. The task of pollenization is left to
unenthusiastic species of flies and beetles. A better solution for the
home gardener is to hand pollinate, using a small, soft artist's brush
to transfer pollen to the stigma. 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 on the brush hairs. The
stigma is receptive when the tips of the pistils are green, glossy and
sticky, and the anther ball is firm and greenish to light yellow in
fruit ripens during a four-week period between mid August and into
October, depending on various factors. When ripe, it is soft and yields
easily to a gentle squeeze, and has a pronounced perfumed fragrance.
The skin of the green fruit usually lightens in color as it ripens and
often develops blackish splotches which do not affect the flavor or
edibility. The yellow flesh is custard like and highly nutritious. The
best fruit has a complex, tropical flavor unlike any other temperate
zone fruit. At present, the primary use of pawpaws is for fresh eating
out of hand. The ripe fruit is very perishable with a shelf life of 2
or 3 days, but will keep up to 3 weeks if it is refrigerated at 40°
- 45° F.
Although pawpaw fruit is not yet a commercially viable commodity, the
domestication process is well underway. Several academic institutions
are setting up seventeen Regional Variety Trial sites. Kentucky State
University is the site of Pawpaw National Clonal Germ-plasm Repository.
The pawpaw has also found its way to several overseas countries, and a
few of these are actively engaged in research. Pawpaw leaves and twigs
contain substances with promising anti-cancer and pesitcidal properties.
A number of mail-order sources of pawpaw plants now offer both grafted
cultivars and seedlings. Most seedling plants have been propagated from
mixed seeds and will eventually end up producing undesirable fruit.
Purchasers are advised to graft such plants to a known cultivar or
order grafted plants initially. Container grown plants are much more
likely to survive transplanting.
When placing an order for a
pawpaw plant, it is helpful to have the Pawpaw Selection Option Chart
below handy. Phoning in the order gives the opportunity to ask
questions and substantiate it.
|| Container Grown (1)
|| Bare Root (2)
on seedling root stock
|CULTIVAR - from shoot/root on own root stock
|SEEDLING - from seed of mixed seed (risky
|SEEDLING - from seed of cultivar fruit
(usually comes fairly true)
|(1) easier to get
established, good survival rate
(2) slower to get established, reduced survival rate
(1990) lists over 60 pawpaw cultivars, many of which are not available
in the nursery trade. The Kentucky State list of cultivars, while not
as extensive, is more current. The following cultivars are among the
best with regard to fruit quality:
Fruit small. Flesh yellow, green skin. Seeds
large. Flavor good.
Similar to Sunflower.
Fruit medium. Flesh golden, slightly yellow skin.
Fruit large. Fewer seed but large. Flesh yellow.
Fruit large. Flesh yellow. Flavor excellent.
Fruit medium large. Flesh golden, yellowish skin.
Few seeds. Flavor good. Purported to be self-fertile.
Fruit medium large. Prolific bearer. Flesh
yellow. Flavor good.
Fruit small. Flesh yellow, green skin. Flavor
Fruit medium. Flesh yellow, light green skin.
Flavor excellent. Prolific bearer.
Fruit quite large. Flesh orange, green skin.
Callaway, M. Brett. Pawpaw (Asimina
triloba): a "Tropical" Fruit for Temperate Climates. New
Callaway, M. Brett. The Pawpaw (Asimina
triloba). Kentucky State University, Frankfort, KY. 1990.
M. Brett and Dorothy J. Callaway. Our Native Pawpaw: The Next New
Commercial Fruit? Arnold Arboretum, Harvard University. Fall 1992, pp
Layne, D. R. Pawpaws. In: Register of Fruit and Nut Varieties, 3d ed.
A.S.H.S. Press, Alexandria, VA, 1996.
D.R. The Pawpaw [Asimina
triloba (L.) Dunal]: A New Fruit Crop for
Kentucky and the United States. HortScience vol. 31, 1996, pp. 15-22.
Peterson, R. Neal. Pawpaws in the Garden, and Pawpaws in the Nursery
Trade. Pawpaw Foundation, 1990.
Peterson, R. Neal. Pawpaw (Asimina).
Acta Horticulture, ISHS. Feb.1991, pp. 569-600.
Reich, Lee. Uncommon Fruits Worthy of Attention. Addison-Wesley, 1991.
Kentucky State University Pawpaw Research Project