Plant Bio: Asimina triloba – Common Pawpaw
With its large, drooping, dark green leaves and fruit reminiscent of the tropics, the Pawpaw doesn’t seem to belong in Southern Ontario. In fact, the Asimina is the only member of the Annonaceae family found outside of the tropics. But we’re pretty lucky to have it.
Native to most of the Eastern United States and the southern tip of Ontario, Asimina triloba grows in temperate woodlands – either in well-drained, rich bottomland or on hilly upland. Common pawpaws can be grown as container specimens, but it is necessary to have a deep container to allow room for the roots. Its dark red flowers appear in early spring, before the leaves grow. These trees can grow to 11m.
Pawpaws’ leaves, twigs and bark contain Annonaceous acetogenins – a natural pesticide that gives these trees immunity from almost all pests. Also, the acetogenins can be used to manufacture organic pesticide.
The pawpaw fruits in September to October. The fruit is a 5-15 cm long, greenish-yellow berry. It looks something like a papaya, which is probably where its name originates. In fact, the fruit tastes somewhat like both banana and mango. It has large seeds embedded in the flesh. Unfortunately, the cultivation of the pawpaw is limited by difficulty in transport – it must be frozen in order to be preserved. However, it is a perfect choice for local produce where available.
Beneficial Chemical Properties:
The pawpaw fruit is a healthful source of good fats, protein (containing more than most fruits), and complex carbohydrates. The tree also has some of the strongest forms of acetogenins of any tree or plant. These long-chained fatty acids fight insects, parasites, lice, and cancer cells. Thus, as well as providing useful pesticide, the pawpaw has great medicinal value as well. It is hailed by some as an alternative cancer treatment, and pawpaw twig extract pills are now available.
Acetogenins from the pawpaw, as well as from less potent sources in the Annonaceae family (graviola, guanabana and soursop), are the only remedy that has proven effective in inhibiting the growth of multiple drug resistant cells. These cells, which constitute about 2% of tumour mass, cannot be destroyed by chemotherapy and will regenerate into a chemotherapy-resistant tumour. Another benefit of pawpaws as compared with most other alternative cancer treatments is that the therapeutic agents in the pawpaw can cross the blood/brain barrier (a bodily protective mechanism) and treat the brain.
Rather exotic but native, delicious, pest-free and medicinal – the pawpaw has it all. These low-maintenance trees would make a great addition to any backyard or neighbourhood garden.