Asimina Triloba: Pawpaw
Shade for first two years, full sun preferable afterwords
Pollination: self-sterile (monoecious)
Chill Hours 400
pH 5.5 - 7
Yield 2 - 4 years (graft, 6 years seedling)
Common Names: Hillbilly Mango, Hillbilly Banana, Indiana Banana, Hoosier Banana, Poor Man's Banana, Pawpaw, Kentucky Banana.
Scientific Names: Species: Asimina triloba Family: Annonaceae (Custard Apple Family)
Uses: Eaten in-hand as fresh fruit or processed into desserts. Twigs are source of annonaceous acetogenins which are being used in the development of anti-cancer drugs and botanical pesticides.
Pawpaws are native to eastern United States and certain strains will grow in the United Kingdom. Preferably they will received 8cm of rainfall per month throughout the year. They have been grown in mediterranean and semi-arid climates, but they may require occasional irrigation during spring and summer if you wish to get them to fruit. Young trees (1 or 2 years of age) may require shade as 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.
Pawpaws can bloom for up to 4 weeks, but without hand pollination, fruit set can be low because bees do not pollinate the flowers, flies and beetles do.
Harvest season can last for up to 3-4 weeks, and different people may prefer pawpaws in different ripening stages, since it can have a fairly dramatic affect on the flavour.
Common descriptions of some pawpaw cultivars often imply they produce fruit that weigh 200g to 350g or more. Many of these cultivars 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.
With its large green tropical drooping leaves and dramatic purple brown flowers in spring, the Asimona Triloba "PawPaw" tree has great ornamental appeal as well. Plant in well drained soil and protect from strong winds and grass competition for the first two years.
The pawpaw is the only temperate member of the tropical Annonaceae family and is the largest tree fruit native to the United States. Pawpaws grow wild in the rich, mesic hardwood forests of 25 states in the eastern United States ranging from northern Florida to southern Ontario (Canada) and as far west as eastern Nebraska. Pawpaws flourish in the deep, rich fertile soils of river-bottom lands where they grow as understory trees or thicket-shrubs.
Growth Habit: 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.
Foliage: 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.
Flowers: 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.
Fruit: 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.
Location: 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.
Soil: 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, alkaline soil.
Irrigation: The pawpaw needs regular watering during the growing season. The soil should be kept moist but avoid waterlogging.
Fertilization: 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.
Pruning: 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.