In April and May, tiny green catkins of the red mulberry flower appear. The plant has small tubular flowers that can reach up to an inch (2.5 cm) in length.The catkins of black mulberry flowers are small, tubular white flowers. This tree blooms every year in spring. Summer is when berries begin to appear and ripen. In early spring, yellow-green catkins hang down.

Some white mulberry trees have flowers of only one sex, while others have flowers of both sexes.Fruits can only come from plants with female flowers. The half-inch to one-inch long fruits look like blackberries and turn from white or pink to deep purple before falling in mid-summer. Some mulberry trees are monoecious, meaning they have either only male flowers or only female flowers. But right next to this type of tree can be a monoecious, with both male and female flowers on the same plant. For many species, being male or female is a full-time job.

It can affect what you wear in person, what sports teams you can join, and even how much money you can make. Male birds often have brighter feathers than their female counterparts, and only male moose have rakes. However, when it comes to mulberry trees, the flower is the only part of the plant that has sex. A mulberry tree is said to be male if it has male flowers that contain the pollen the female flowers need to produce fruit. A tree is said to be female if all of its flowers are female and it has a stigma that collects the pollen and a way for the pollen to reach the ovary at the base of the tree. The terms "male tree" and "female tree" do not apply to trees that have both male and female flowers or to trees whose flowers can change from one sex to the other.

That means mulberry trees with all male flowers, at least for now. And those mulberry trees that have only female flowers. Many mulberry trees are none of these things. Although mulberry trees may not always be male or female, each mulberry flower has a gender that you can tell at a given time, even if it changes sex. Mulberry flowers grow in clusters called "catkins" that hang down. The flowers of each of the three mulberry species look slightly different. Black mulberry (Morris nigra) flowers look like small, green catkins with spikes.

Red mulberry (Morus rubra) has light green catkins, and white mulberry (Morus alba) has small green spikes.But all types of mulberry male flowers are similar in how they work. The four reproductive parts of the male mulberry flower are called stamens, and they sit on stems called filaments. The female flower has a reproductive organ, called a pistil, attached by what looks like a thread. Pollen arrives at the stigma on the pistil, and the style is guided to the ovule at its base.

Can you see the organs in the flowers that are so small? Maybe, if you look closely at the flower with a magnifying glass. If the flower does not have a stem-like growth, it is a female flower. But the length of the flower catkins is a better way to tell whether a plant is male or female. Male catkins are up to 2 inches long and narrow, while female catkins are only about 1 inch long and wide.