Pawpaw - cultivation instructions and nutritional value

The taste of the Indian banana is somewhat reminiscent of sweet, ripe bananas. More specifically, a tropical fruit cocktail made from banana, mango, pineapple and vanilla. Asimina triloba is still hardly known to us. Belongs to the soursop family (Annonaceae). The names Papau, Paw Paw or Pawpaw are perhaps a little more familiar. In southeastern North America, where the pawpaw tree is native, its fruits are also called Poor Man's Banana or Hoosier Banana. The fact that this fruit has considerable significance in its homeland is evident from the fact that places, schools, rivers and lakes, and even cities, are called “Paw Paw”.

So why is this fruit so interesting?

In our fruit markets you occasionally come across the closest relatives of the Indian banana. However, these are the fruits of tropical or subtropical trees that are not hardy under Central European conditions. The taste of the Indian banana is also reminiscent of tropical fruits. In contrast, however, it is the only winter-hardy representative of a subtropical to tropical group of trees that is cultivated particularly for its edible fruits.

Appearance and characteristics

The pawpaw is an extraordinary tree. This is due to its unusually large leaves, characteristic growth habit and wonderful autumn color. More rarely, it develops into a deciduous large shrub about 3 to 5 m high. It usually grows tree-shaped and can sometimes reach a height of up to 8 m when fully grown. In our latitudes, however, height growth will occur at around 5 to 6 m. The grafted plants develop a straight, continuous leading shoot. Its tightly closed crown is initially narrowly conical, later broadly rounded to oval. Occasionally plants produce root suckers at some distance from the trunk. This is not only the case with seedlings, it can also be observed on grafted plants. Budding occurs relatively late, only then do the 12 to 25 cm large, very decorative leaves develop. They are arranged alternately and give the plants a “tropical” look. The Indian banana trees cannot be overlooked, especially when their foliage turns bright yellow in autumn. The flowers open before the leaves emerge, which occurs very late. Depending on the variety, geographical latitude and altitude, the flowering period is around six weeks. It can start from March and extend into May. In our latitudes this happens around the end of April/beginning of May. Now the thick, swollen, rounded flower buds that formed in the fall of the previous year open. They are red to chestnut brown, bell-shaped, about 3 to 5 cm tall and are located in the leaf axils of previous year's shoots. Their structure is very simple because they only consist of 3 sepals and 2 rows of 3 petals each. What is interesting, however, is that each individual flower has several ovaries. This also explains why a single flower develops not just one, but several fruits (clusters).

Pollination

The flowers are not pollinated by bees, but primarily by flies, beetles and the wind. Since the flowers are self-sterile, multiple clones or varieties must be planted to ensure good fruit set. This is because the female flower parts (stigmas) are already receptive to pollen when their own stamens are not yet fully developed. If they then release their pollen, the stigmas have already withered. However, this problem can be avoided by planting around 2 to 3 self-fertile varieties ('Overleese', 'Sunflower' and 'Prima'). In America, hand pollination with a brush is also recommended. However, tests in Germany showed that this does not result in significantly better pollination or fertilization. According to information from Switzerland, pollination by hand is recommended, as a large difference has been found between naturally pollinated and hand-pollinated plants. Of course, this results in a significantly increased workload. In addition, the fruits of hand-pollinated plants are said to contain more seeds.

Fruit

The fruits of the wild form of Indian bananas are 7 to 9 (up to 15) cm long and 3 to 5 cm wide, oval to sausage-shaped, greenish and yellowish berries when ripe. They rarely develop individual fruits; they are usually grouped into fruit groups (clusters) of 3 to 9 individual fruits. Auslese and varieties can grow up to 15 cm tall. The individual fruits weigh between 60 and 240 g, but can also reach a maximum weight of up to 470 g. At about 1.3 to 3.0 cm, they have relatively large seeds that are dark brown to black in color. Fortunately, the fruit varieties usually only contain 8 to 10 bean-sized seeds in 2 rows. In contrast, the fruits of wild plants or seedling plants can sometimes contain 10 to 14 seeds. The flesh of ripe pawpaws is soft and tender, enclosed in a thin greenish to greenish-yellow fruit shell. Even if the shape of the fruit has nothing in common with a banana, it is not surprising that it was still given the name “Indian banana”. The consistency of the creamy white to yellowish flesh actually resembles that of a banana or a ripe avocado. The aroma of the pulp is also somewhat reminiscent of sweet, ripe bananas, mango, pineapple and vanilla.

Ripening

The best time to ripen is when the peel turns from fresh green to slightly yellow. Brown or black spots may develop on the peel of fully ripe fruits. Although these in no way affect the taste, they do make the fruit a little less attractive. This is of course very hindering for the sale of Pawpaws. Therefore, they must be treated with the utmost care and are not easy to transport. Pawpaw fruits ripen over a period of about 4 weeks from mid-September to mid-October. The fruit is ripe when its skin can be easily indented by gentle pressure with your fingers (similar to peaches). When ripe, they exude a very characteristic sweet scent of tropical fruits. Ripe fruits can be stored for 2 to 3 days. Fruits that are harvested (or fallen) just before they are fully ripe ripen well within a few days. Due to the long ripening time of the fruits, 3 to 4 picking passes must be carried out. It takes about 5 to 6 years for the first fruit yield to appear.

Nutritional value and ingredients

Pawpaw fruits have a very high nutritional value with 80 kcal per 100 g of pulp. In terms of ingredients, they are similar to bananas. They have 1.2% protein, 1.2% fat (with the peel), 18.8% carbohydrates, 18.3 mg/100 g vitamin C. The high mineral and amino acid content is also worth mentioning, as these are much higher than apples, oranges or bananas. Indian bananas are suitable for raw consumption. You eat them by cutting them in half and scooping out the soft, creamy flesh, similar to kiwis. It is best to remove the seeds while spooning them out. You can also puree the fruits and use them to make fruit cocktails, ice cream, milkshakes or mixed juices. Alcoholic drinks can also be made from it. However, there are also people who do not tolerate pawpaw fruits well (as was also found when eating mini kiwis); skin rashes, nausea or diarrhea may occur after consumption. Pawpaws also allegedly contain anti-cancer substances.

Location, planting and care

The Pawpaw prefers humid continental climates with moderately moist, nutrient-rich and slightly acidic soils. Additional irrigation (drip irrigation) is appropriate if you want to use the Indian banana commercially. Since waterlogging is not tolerated, it is important that the soil is permeable. The most suitable areas are areas with a favorable climate (such as a wine-growing climate), so that the fruits ripen in time before the first frosts. Nevertheless, the pawpaw requires a minimum of 400 hours (about 16 to 20 days) of winter cold and at least 160 frost-free days. However, due to their deep winter dormancy, the plants are very frost hardy and can tolerate temperatures down to -25 °C. But they can also cope with temperatures of +35 °C. However, they are sensitive to high levels of air dryness, dry winds and cool, humid summers.

An area of approximately 4 x 2 m or 4 x 3 m should be available per tree. The side shoots grow around 15 to 30 cm annually. Apart from additional irrigation, no other maintenance work is necessary. Pruning measures are usually not necessary and are limited to removing injured or frozen parts of the plant. You may want to remove competing shoots from spindle trees and divert steeper branches. In order to keep the trees low, the crown can be thinned out; a light thinning cut is also recommended on older plants. There are currently no plantations of Asimina triloba. There are experimental plantings in Italy, Germany, Austria and Australia. The fruits in the local markets come from home gardens or, in America, from wild places. Wild forms or rootstocks can be easily propagated by seeds (after cold-warm stratification). But not all plants grown from seeds produce tasty fruits; some can have an unpleasant aftertaste. It is therefore absolutely advisable to use refined varieties. Indian bananas develop a taproot and react very sensitively if these are injured.

The most famous varieties

There are more than 50 selections in the United States, but only about 15 to 20 of them are used commercially. The self-fertile varieties 'Overleese' and 'Sunflower' are mainly offered. Overleese produces large fruits (200 to 250/max. 390 g) with an average fruit yield of 7.5 to 11.0 kg - that is around 30 to 65 fruits per tree. Its taste is fruity and very good and ripens at the end of September. Sunflower is the second self-fertile variety with also very large fruits (160 to 200/max. 325 g) and high fruit yield (8.5 to 12.0 kg, that is 45 to 75 fruits per tree). The taste of this variety is also very good, it was the most popular variety at tastings. Their ripening period extends from the end of September to mid-October.