Papaya

Papaya trees are some odd critters. Besides being delicious, they have three genders.

Papaya (Ivar Leidus) CC BY-SA 4.0

In a complex reproductive arrangement similar to avocados, papaya flowers can be male, female, or hermaphroditic. Male flowers only produce pollen. Female flowers always produce fruit, but it’s only edible if the flower was pollinated. Most commercially grown papayas are from hermaphroditic trees.

What’s in a name?

Also known as pawpaws, there’s more to papaya than the fruits seen in grocery stores. Those are tropical papayas. There are also mountain papayas and Eastern North American pawpaws. Each of these plants comes from a completely different family. Tropical and mountain papayas are distantly related to Brussels sprouts and they grow best in USDA Hardiness Zones 9–11. North American pawpaws are cousins to the cherimoya. Let’s see what each has to offer the home gardener.

Tropical papayas

Tropical papayas (Carica papaya) originated in Mesoamerica and southern Florida. India now produces nearly half of the world’s papaya supply. These trees are tall (15 to 30 feet) and narrow, with the fruit growing in clusters just under the canopy. Fruits are initially green and then turn yellow or red, depending on the cultivar.

Tropical papaya trees are frost-sensitive. Temperatures below 29°F are often fatal. They prefer loose, sandy soil with a pH of 6.5–7.0, though they can manage 4.5–8.4 if other conditions are good. Standing water can kill a papaya tree in only 24 hours. These trees are highly susceptible to the papaya ringspot virus. Researchers found that crossing tropical papayas with mountain papayas made the trees more resistant to papaya ringspot virus and black spot. Unfortunately, these crossbreeds are sterile, and most papaya trees are grown from seed.

Mature papaya tree (Max.kit) CC BY-SA 4.0

​Mountain papayas

Mountain papayas (Vasconcellea pubescens, aka Carica pubescens) are native to the Andes. They love higher elevations. These evergreen shrubs rarely grow more than 15 feet tall, though they can reach twice that height. These shrubs grow so quickly that they are considered invasive in some areas. Fall armyworms can be a problem for mountain papayas.

Mountain papaya tree (Rik Schuiling) CC BY-SA 3.0

Mountain papaya fruit (Michael Hermann) CC BY-SA 3.0

If you can find (or grow) them, mountain papayas contain significantly more antioxidants, minerals, and vitamins than other types of papaya. They also provide 5–8 times the helpful digestive enzyme papain found in other papayas.

Eastern North American papayas

Eastern North American pawpaws (Asimina triloba), also known as wild bananas, tolerate colder temperatures than their fruity cousins. They occur naturally in USDA Hardiness Zones 5–9. But you don’t see them in stores because they start to ferment as soon as they ripen.

Pawpaw tree and fruit (USDA) Public Domain

These clonal understory trees produce fruits with a custard-like flavor said to be something like a tropical milkshake. The beautiful purple flowers are perfect, which means they are both male and female. They are imperfect because they stink. More on that in a minute. And you will need two trees to get a good harvest.

Pawpaw flowers begin female (left), then turn male and produce pollen (right). (Cbarlow) CC BY-SA 4.0

If you decide to grow pawpaws, the seeds must be stratified in cold moist storage at 35–45°F for 60–120 days to germinate. These seeds will not grow true to the parent, and cuttings are generally unsuccessful. Root suckers will be clones of the parent tree. You can also use chip budding or whip grafting to propagate your very own pawpaw tree. Some state Divisions of Forestry offer grafted cultivars to the public.


​Papaya trees are low-maintenance once established, but pollination can be a problem. The flowers smell bad because blowflies are common pollinators. Some people spray their trees with fish emulsion or hang rotted meat on the branches to increase pollination rates. Hand-pollination is another option.

Pawpaw fruit (Manuel.conde) Public Domain

The fruit is a botanical berry and can become heavy enough to break branches, so supporting poles may be needed. The bark, leaves, and twigs of pawpaws contain natural insecticides (acetogenins) that keep most pests away. Fruit flies and whiteflies may still show up. Zebra swallowtail caterpillars love to feed on these trees, but this is generally not a problem for the trees or the caterpillars, and the toxins consumed provide natural protection against predators for the adult butterflies.

Caring for a papaya tree

Common diseases associated with papaya trees include anthracnose, black leafspot, papaya mosaic virus, phytophthora blight, and powdery mildew, along with the dreaded papaya ringspot virus.

Before you start working with a papaya tree, you need to know that the latex from unripe fruits can be extremely irritating. Many people learn the hard way that they are allergic. Sadly for those individuals, this latex is commonly used as a meat tenderizer.

Did you know that you can use papaya seeds as a pepper replacement? Now you know.