Red mulberry leaves are heart-shaped with sizes ranging from 3 to 5 inches (7.6 to 12.7 cm) in length and 2 to 4 inches (5 to 10 cm) in width. They exhibit a dark green color and can vary from unlobed to deeply lobed, often with a rough upper surface and soft, hairy underside. New shoots tend to have lobed leaves, while tree crowns display more unlobed leaves. The leaves turn yellow in fall and possess toothed edges.

The flowers of red mulberry are unisexual and greenish, appearing in small, drooping, catkin-like spikes. Male and female flowers generally grow on separate trees (dioecious), with both types blooming from April to May. The male catkins are slender and around 1.5 inches (4 cm) long, while the female spikes are shorter and more compact. The unassuming greenish hue and small stature make the flowers a subtle but crucial identification feature.

The stem of red mulberry is characterized by its brown, reddish-brown, or gray bark, which is generally smooth. Twigs are adorned with scattered white lenticels and often appear more smooth. Young shoots typically present a light green hue and are usually glabrous. Branches are slender but sturdy, providing a distinct visual contrast due to their smooth texture and occasional lenticels. This combination of colors and textures aids in distinguishing red mulberry's stem from other species.

The fruit of red mulberry appears as sweet, blackberry-like clusters, initially reddish then maturing to a rich dark purple hue. Each berry is succulent, with a soft, juicy texture savored when consumed directly from the tree. Measuring about 1-1.5 inches (2.5-3.8 cm) in length, these aggregate fruits are coveted for their delectable flavor, widely utilized in homemade jellies, jams, and wines. Despite their allure, these fruits are seldom found in commercial markets due to their brief longevity post-harvest and their susceptibility to damage during transport. The fruiting season is brief, typically observable from May to June.