Male & Female Stage Blossoms on Fruit Trees

Flowers on some plants are either male or female; other flowers have both male and female parts. More rarely, flowers change or pass through sexual stages, changing from one sex to another. Protoandrous flowers begin as male flowers and change to female. Protogynous flowers begin as females and change into male. Fruit trees with flowers that go through sexual stages include the avocado (Persea americana), the papaya (Carica papaya), the sugar apple (Annona squamosa) and the paw paw (Asimina triloba).

Flower Basics

The male stamen of a flower consists of an anther, covered with sticky pollen, that sits atop a slender filament. The female stigma that receives the male pollen sits atop an ovary that looks like a miniature fruit. Pollen must be transferred from the anther to stigma for the flower to be fertile and bear fruit. There are variations to how those the male and female parts appear when you look inside the flower of a particular fruit, but those are the essentials.


Protogynous avocado flowers open for two days, but with different stages of opening for male and female parts. An avocado flower first opens as female for two to four hours, exposing its stigma to insects bearing pollen. On the second day the same flower opens as a male with an exposed stamen. In some avocado varieties, the female flower opens early in the morning and closes in late morning or early afternoon. On the afternoon of the second day it opens as a male. Other varieties open as a female in the early afternoon, close in late afternoon, and reopen in the male stage the following morning.


Summer heat can sometimes cause papaya flowers to turn from male or bisexual to female.

Papayas may bear female or bisexual flowers containing both sexes on short stalks or clusters of male flowers on clusters 5 to 6 feet long. Papaya flowers are not genetically programmed to routinely change sex, but in hot summer weather male or bisexual flowers will sometimes change into females. If no male or bisexual flowers are nearby to provide pollen, female plants may not yield papayas. Papayas are sometimes called paw paws, but they are not the same as the North American paw paw (A. triloba).

Sugar Apple

The petals of the sugar apple, also called the custard apple, open slightly during the day revealing a glistening surface of the female stigma, indicating that it is receptive to pollen. The flowers open wide the next morning to reveal the brownish male anther. By late afternoon the anthers begin releasing pollen. The practical effect of sugar apple flowers changing sexes by stages is that cross-pollination among different flowers is necessary, and they are often pollinated by hand to increase production.

Paw Paw

The flowers of the North American paw paw are protogynous. Their petals turn from green to purple and are tightly packed in the female stage; their sticky stigma are shiny and green. The closed petals force insects bearing male pollen to brush against the stigma. Meanwhile, the male anther is tucked into a tight, green ball. As the flowers turn male, the petals open and turn a dark purple, and the flowers emit a strong odor. The ball of anthers opens and the anthers turn from green to brown. The odor and open petals invite browsing insects to enter and bump up against the pollen on the anthers. The effect of this changing of sexes is that paw paws are self-incompatible, meaning they require pollen from an unrelated paw paw tree. Pollination is further complicated by the fact that bees show no interest in paw paw flowers; they are pollinated by flies and beetles. If no pollinating insects are available, you have to pollinate paw paw flowers by hand.

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