Common Name: Papaw

General Information

Asimina triloba is a deciduous shrub or small tree with a spreading crown; it can grow from 1.5 - 11 metres tall, occasionally to 14 metres. The bole (when produced) is straight and up to 20cm in diameter, exceptionally to 30cm. Plants often spread by means of root suckers and can form colonies or thickets[, ].
The plant produces a delicious edible fruit which is a potentially commercial crop[]. The wild-collected fruit is often sold in local markets in America[]. The tree also has traditional uses as a medicine and source of materials.

Known Hazards

The seed contains a toxic alkaloid and is poisonous[, ].
The leaves can cause minor cases of dermatitis in a small number of sensitive people[, , ]. Other reports say that handling the fruit can cause dermatitis[, , ].
Eating the fruit can cause stomach upsets for some people, though most people can enjoy them without problems[, , ].

Botanical References

, ,

Range

Central and eastern N. America - Nebraska to southern Ontario and New York, south to Texas and Florida

Habitat

An understorey tree of woodlands, growing in deep rich moist soils of river valleys and bottomlands, often forming dense thickets[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	4.50 m
Growth Rate	Slow
Pollinators	lies, Beetles, Self
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

Asimina triloba is a plant of the temperate to subtropical zones of North America, where it is found at elevations up to 1,500 metres. It grows best in areas where annual daytime temperatures are within the range 12 - 22°c, but can tolerate 8 - 32°c[]. When dormant, the plant can survive temperatures down to about -25°c or perhaps lower, but young growth can be severely damaged at 0°c[]. It prefers a mean annual rainfall in the range 400 - 1,200mm, but tolerates 225 - 1,500mm[]. Trees require long hot summers if they are to produce well, in the cooler, moister climate of Britain, for example, they often remain shrub-like and seldom ripen their fruit[].
Prefers a deep, rich loamy to clay soil with plenty of moisture. It grows wild in shady forests, but fruits best in a sunny position[, , , ]. Prefers a pH in the range 6 - 7.2, tolerating 5.2 - 7.5[].
The tree commences bearing in 4 - 6 years from seed and yields up to 30 kilos per tree[]. There are some named varieties[].
Flowers are formed in the leaf axils of wood produced the previous summer[, ].
Established plants resent root disturbance, the best plants are obtained by planting them out into their permanent positions as young as possible though young plants should be given some protection for their first year or two[].
The large leaves can be up to 30cm long - they emit a heavy unpleasant odour when crushed[, , ].
Plants are untroubled by pests or diseases[].

Edible Uses

Edible fruit - raw or cooked[, , , , , ]. Of variable quality, some forms (with orange skins) are exquisite with the flavour of banana custard whilst others (with yellow, white or dark brown skins) can be unpleasant[, , ]. Another report says that the white-fleshed fruits are mildly flavoured and later ripening than the orange-fleshed fruits[]. The fruit can also be used for making preserves, pies, ice cream and other sweet desserts[]. The bottle-shaped fruit is of a very good size, it can be up to 16cm long and 4cm wide, containing 3 or more seeds 15 - 25mm long[, , ].
The fruit falls from the tree in autumn and is then stored until fully ripe[].
Although enjoyed by most people who eat them, the fruits can cause gastro-intestinal upsets for some people[].

Medicinal

The fruit is used as a laxative[].

The leaves are diuretic[]. They are applied externally to boils, ulcers and abscesses[, ].

The seed contains the alkaline asiminine, which is emetic and narcotic[, ]. They have been powdered and applied to hair to kill lice[].

The bark is a bitter tonic[]. It contains the alkaline analobine, which is used medicinally[].

Agroforestry Uses:

The tree can appear as a pioneer species on clear-cut land, though it is not normally among the very earliest pioneers. Sites that have been clearcut may need to be treated to suppress this species since it can outcompete valued timber species. It creates heavy shade that reduces seedling recruitment of trees such as white oak (Quercus alba) and shagbark hickory (Carya ovata), whilst encouraging shade-tolerant seedlings of species such as sugar maple (Acer saccharum)[].

Other Uses

A fibre from the inner bark is used for making strong rope and string[, , , , ].

The seed has insecticidal properties[].

A yellow dye is made from the ripe flesh of the fruit[].

Wood - light, soft, weak, spongy, coarse grained[, ]. It weighs 24lb per cubic foot[]. It is not used commercially[].

Propagation

Seed - best sown as soon as it is ripe in a cold frame[]. The seed usually germinates in 1 - 3 months at 15°c[]. Stored seed requires stratification, it has embryo dormancy and an impermeable seedcoat and can take up to 18 months to germinate[, ]. Dried seed quickly loses its viability. As soon as the seedlings are large enough to handle, prick them out into individual pots and grow them on in the greenhouse for t least their first winter. If trying them outdoors, plant them into their permanent positions in early summer once the plants are more than 15cm tall. Consider giving them some protection from winter cold for their first winter outdoors.
Layering.