Pawpaw - is native to eastern to central North America. As the only genus from the Annonaceae family, it can also be cultivated in Central Europe, especially in wine-growing regions. As the climate continues to warm, other locations used for fruit growing will also become possible.

As an interesting, exotic-looking plant, Asimina triloba could and should increasingly find its way into special nursery ranges such as "Snack Garden", "Exotic Garden" and "New Products" due to its many positive properties.

The natives of North America have already used the fruits. Numerous varieties are now available in the USA, where Pawpaw is cultivated as a single-shoot small tree. Without intervention it can reach 5 to 10 m, especially when it is solitary - as in some botanical gardens in Europe. For fruit-growing use, for example, spindle training with lower tree heights (3 to 4 m) is an option.
When looking for new products in the woody sector, increasing demand for Asimina triloba can initially be seen in the hobby sector. Reasons for this include: the weak and slow growth, so that the frost-hardy and disease-resistant deciduous tree remains small or can be kept small. The ornamental value is expressed in the bell-shaped purple-violet flowers and the autumn color with yellow foliage. And last but not least, the edible fruits, which ripen in late September to early/mid-October. According to American information, they have high nutritional value with anti-carcinogenic properties.
Of the numerous names for the fruit, the term "Indian banana" seems to be the most suitable - also effective in advertising with regard to the market launch of this new type of fruit. It's actually unbelievable that Pawpaw is so far largely unknown to us. The search term “Pawpaw” yields around 9 million entries on Google (compared to Apple: around 23.8 million mentions)! In the USA there are information sites, chats, recipes, sources and even a foundation (The Pawpaw Foundation). Pawpaw is also used in the university sector. 

Several years of experience in Veitshöchheim

Reason enough to take a closer look at this innovation. At the Bavarian State Institute for Viticulture and Horticulture Veitshöchheim in spring 1998, 5 trees of 5 varieties were planted as two-year grafts (rootstock: seedling) from the Swiss tree nursery Andreas Hess (CH-8265 Mammern) at a distance of 4 m x 3 m. The single-shoot tree initially grows very slowly, branches well (mainly at a 45° angle) and produces short new shoots 15 to 30 cm long every year. When training the tree, only the competitive instinct was removed in the first few years. However, it takes 3 years until the first flowering occurs. Before the leaves emerge, they appear individually on the annual wood as purple-colored bells that can be up to 5 cm wide and are therefore intended to attract insects for pollination. The flowering time is around mid to late May, i.e. after the ice saints and after the apple blossom.

The Indian banana relies on cross-pollination. Only a few varieties are classified as partially (e.g. 'Sunflower') or fully self-fertile (e.g. 'Prima'). In commercial cultivation, two varieties should definitely be planted. The flower contains several ovaries, so that pollinated organs can produce up to 5 individual fruits in a cluster. Nevertheless, the fruit set and therefore the yield is rather low. In Europe, certain insects and pollen-carrying beetles that ensure better pollination in North America are missing. Bumblebees and bees can also be found here, but the "stinky" smell of the flowers makes them unattractive to our main pollinators. Hand pollination is therefore recommended, although this is unlikely to be practiced in commercial cultivation. In any case, only fully or partially self-fertile varieties such as 'Sunflower' or 'Prima' should be grown, where the yield potential is generally higher. 

The ripening period is from the end of September to mid-October. In the approximately three-week ripening window, 2 - 3, possibly even 4 picking passes are required. The exact harvest time is somewhat difficult to specify. It has proven useful if the skin color of the elongated oval to club-shaped fruits changes from green to slightly yellow-green.
Harvesting must be carried out carefully, as the peels can easily become bruised, which can also be caused by friction from fruit hanging in clusters.
The fruits must be stored cool (2 to 3 °C), otherwise they will ripen quickly and should be consumed as soon as possible. This is similar to the "real" banana - as well as the fact that the peel quickly turns yellow to brown, the flesh is soft, very sweet and even slightly fermented due to the rapid breakdown of the fruit acids.

The taste is sweet, the aroma is a mixture of banana/mango/melon with a slight hint of vanilla – fruitier than banana. The consistency of the creamy white to yellowish flesh is similar to a banana to avocado. The fruits are eaten without the peel: either peeled or - similar to a kiwi - cut open and then spooned out. However, the bean seed-sized seeds, which are distributed throughout the entire fruit, are a nuisance.

In addition to fresh consumption, puree can be made to use with ice cream, milkshakes, mixed juices - in principle like banana. A sponge cake with pawpaw puree tastes fruity. The use of the kernels or leaves, e.g. for tea, creams or pharmaceutical purposes, should be examined.

Yields

The yields were assessed in the first years for 'Sunflower' and 'Overleese' and extrapolated based on the number of fruits and average fruit weight, recorded exactly from the 9th year onwards. The other varieties fell sharply.

Yields vary depending on the variety, training (crown volume) and pruning interventions. In order to maintain tree height, more pruning interventions are required. Consequently, the yield potential remained at 7 - 10 kg in years 11 - 13. The late frost year of 2011 with only 3 kg of fruit per tree was followed in 2012 (15th leaf) by “record tree yields” of up to 34 kg ('Sunflower'), up to 25 kg ('Overleese') and the 'Prima', which was only in its 5th leaf, with 12 kg.
In 2012, ‘Davis’ fruited for the first time with very convincing fruit quality. The slightly lower-seed varieties from Neal Peterson/USA have not yet produced any yield.. From a large number of seedlings, 6 were shortlisted. 

Growth and tree characteristics

The varieties grafted onto Asimina triloba seedling grow under the Veitshöchheim conditions (sandy loam, soil value 28, humus content around 1%, pH value 7.2 - 7.3, dry summer location, 8th foliage with drip irrigation) in the first 5 years (very slowly. Supplemental irrigation from the start would certainly have increased growth and possibly initial yields. The well-branched trees form pyramidal, dense crowns when trained as spindles. The side shoots, which usually branch off at 30 to 45° angles from the central axis, grow by around 15 to 30 cm every year. 

Apart from removing competing shoots and diverting steeper side branches, no further pruning or shaping work has been necessary so far. The large, approximately 20 to 25 cm long leaves thicken the crown, which is thinned out after the 10th leaf, thus reducing the tree height. Another more severe pruning took place after the 15th year (2012/13).

Since the pawpaw fruits on last year's new growth, a slender spindle could also be trained with narrow tree spacing (e.g.: 1 m). However, this requires annual pruning interventions (cutting on stubs to encourage one-year-old fruiting wood). 

There were no pests or winter frost damage to wood or flower buds (lowest temperatures: down to -26 °C; repeated years with -18 °C have been survived without any problems). Only the extreme late frost on May 3/4, 2011 resulted in flower damage and reduced yield. Since no fungicidal or insecticidal measures were required, pawpaw seems predestined for organic cultivation. There are specific pests in the USA that are said to not cause any serious problems. 

Fertilization can be based on pome fruit. Nitrogen was administered at an annual rate of 50 kg N/ha, with Nmin contents of 10 to 15 kg/ha measured annually.

Evaluation

As an interesting, exotic-looking niche product, Asimina triloba could and should also be cultivated in Germany - at least for the local market / direct sales - due to its many positive properties. This is supported by the novelty value, exoticism, robustness, problem-free cultivation, possible organic cultivation, little cutting effort, cheap ingredients (positive values of amino acids, higher values of vitamins A and C than, for example, apples, but also many calories!) and the positive, advertising-effective name "Indian banana". 

In addition to cultivation in wine-growing areas, other fruit-growing areas are also being considered due to global warming. Serious disadvantages are the short shelf life, browning of the fruit peel, the hesitant and delayed yields that are significantly lower than apples, problems with pollination, procurement (especially larger quantities) and the price of young trees - at least in Europe (low supply, slow growth of the seedling rootstocks, poor grafting rates). 

Asimina triloba must be introduced onto the market across Europe, advertised and understanding must be raised about the “inconvenient” nature of consuming the fruit. Information materials (handouts) about the fruit are required. Otherwise, the pawpaw remains an exotic niche. It can help some direct selling fruit growers to stand out from their competitors in their product range. 

Especially in years with high yields in self-sufficient cultivation, where sales of the main crops are usually sluggish in autumn, interesting, innovative products on offer can help to increase customer frequency and thus promote sales of apples & Co.
Even if three varieties stand out from a small range in Veitshöchheim: 'Prima', 'Sunflower' and 'Overleese', other varieties should be examined. While many tree nurseries in the USA offer young plants at much lower prices, the offer in Europe has so far been mainly limited to shipping container plants to private customers. In Germany, but also in neighboring countries, well-stocked tree nurseries and specialist garden centers, mail order companies and specialty nurseries offer this new type of fruit.
Depending on the growth rate of the location and the intended cutting intensity, the planting distances can be 4.0 - 4.5 m x 2.0 - 2.5 m; with a slim spindle also underneath. In order to counteract the slow growth in the first few years, additional irrigation on light soils or in dry areas as well as a good supply of nutrients is recommended.