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Pawpaw |
Pawpaws (Carica papaya) probably originated in Central America, where they were widespread before the first European explorers arrived. Cultivation of the pawpaw spread throughout South America during the early part of the sixteenth century and the plant was then carried to the Philippines by the Spaniards around 1550, from where it was transported throughout tropical Asia. Today, major pawpaw producers are Brazil, Indonesia and India who export the fruit to many countries, including the UK.
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Although the pawpaw is often called a tree, it is in fact a giant herbaceous plant, up to 5 m tall. Its hollow stem is grey or green in colour and bears large leaf scars along its entire length. Surmounting the stem is a tuft of large dark green leaves, each up to 75 cm across and deeply divided into approximately 7 leaflets which are in turn further subdivided. The plant is very fast growing, bearing flowers and then fruit within a year of planting. Pawpaws are usually dioecious, with flowers of different sexes being produced on different plants. The trumpet-shaped male flowers are borne in long hanging inflorescences (flower heads) whilst the larger female flowers, which have five free petals, occur in the leaf axils (where the leaf stalk joins the stem), either singly or in small groups. Both male and female flowers are pale yellow and fragrant. When they are cut back, some male plants undergo a change of sex, producing female flowers and then fruits on the new shoots which develop. |
Pawpaws are very popular in tropical fruit salads. They are also made into juices, jams and icecreams. In the tropics, pawpaw leaves are wrapped round meat to tenderise it during cooking. This property of the leaves is due to a protein-degrading enzyme, papain, contained in the plant's milky latex. This latex is collected as it oozes from slits made in the stem bark or the immature fruits. Papain is a major constituent of many meat tenderisers but it also has a wide range of other uses. It is used medicinally to aid digestion as well as in the treatment of slipped discs. Some brands of beer are treated with papain to break down proteins which would cause haziness on chilling. It is also used in the manufacture of chewing gum, toothpaste and cosmetics, including face-lifting treatments. In the textile industry papain is used during the cleaning of silk and to impart shrink resistance to wools. In the tropics, people have found many and various medicinal uses for pawpaw, providing treatments for complaints ranging from rheumatism to warts. Strips of the fruit are laid on infected wounds to make use of its germicidal properties.
Pawpaw does have certain adverse side-effects - its latex is irritant and can cause dermatitis and severe stomach upsets. The fruit can also give rise to allergic reactions.
In the UK pawpaws can only be grown indoors because they require high temperatures and humidity. However, they are unlikely to grow well in centrally heated rooms because they cannot tolerate a dry atmosphere. Generally the plants are best cultivated in a glasshouse or conservatory.
Washed seeds should be sown on a compost rich in organic matter and, under light conditions at temperatures of 20-25°C, they will germinate within 2-4 weeks. After germination, careful watering is necessary to prevent fungal infection and because the plants will not tolerate waterlogging. They grow rapidly at these high temperatures and can produce flowers and fruit within 18 months. Both male and female plants are necessary for fruit production. They are very susceptible to pests such as whitefly and red spider mite but spraying with tepid water reduces the danger of infestation.
Another exotic addition to the fruit market in this country is the babaco (Carica pentagona), which is possibly a hybrid of the pawpaw. Its yellow five-angled fruits, reaching 30 cm in length are usually more or less seedless. Babaco is rich in vitamin C and has similar digestive properties to the pawpaw. It can be eaten raw or made into juice for a refreshing drink, but is more commonly cooked in syrup as a dessert. Although the babaco originated in the high regions of Ecuador, it is now also grown in New Zealand and Guernsey.
A pawpaw plant is cultivated in the Palm House and a babaco in the Temperate House.
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