Mulberry trees (Morus genus) are deciduous trees known for their sweet, edible fruit. These fast-growing trees are found across many temperate regions, and different species have been cultivated globally for centuries. While the trees share a general form, identifying a mulberry relies on specific visual characteristics related to its leaves, bark, and fruit. A closer look at these features helps distinguish between the most common species, such as the native Red Mulberry and the widely introduced White Mulberry.
Leaf Shape and Variability
The foliage of the mulberry tree is a reliable visual identifier due to polymorphism, meaning a single tree can display leaves of many different shapes. You can often find unlobed, heart-shaped leaves growing next to leaves with two or three deep lobes, sometimes described as mitten-shaped. Lobed leaves are common on young shoots, while mature branches tend to have more unlobed leaves. All mulberry leaves are alternately arranged along the stems, have finely serrated edges, and their texture—ranging from glossy to rough—provides clues for species identification.
Trunk Bark and Overall Tree Form
Mulberries are small to medium-sized trees, typically growing between 30 and 60 feet tall. They often have a relatively short, crooked trunk supporting a broad, spreading crown with dense branches. The bark is typically grayish-brown, ranging from slightly rough to deeply furrowed with maturity. Younger branches may display an orange-brown tint, and cutting a twig often reveals a milky sap.
Characteristics of Mulberry Fruit
The mulberry fruit is a multiple fruit—a fleshy cluster of many small drupes—rather than a true berry. These fruits resemble an elongated raspberry or blackberry and grow to be one to two inches long. They transition from small, firm green or white structures to shades of pink and red as they ripen. When fully ripe, the color can range from white or pink to deep purple or black, and the dark juice is well-known for its staining quality.
How to Differentiate Common Mulberry Species
The most frequently encountered species are the White Mulberry (Morus alba), the Red Mulberry (Morus rubra), and the Black Mulberry (Morus nigra). Note that the common name, such as “White Mulberry,” does not reliably indicate the color of the ripe fruit, which can be black on a White Mulberry tree. Therefore, a more reliable method of identification is to examine the leaf texture and the bark structure.
The native Red Mulberry (M. rubra) is identified by its leaves, which are noticeably rough on the upper surface, and its grayer bark with straight, scaly ridges. In contrast, the introduced White Mulberry (M. alba) typically has smoother, often glossy leaves and lighter bark with thick, braiding, tannish-brown ridges. The Black Mulberry (M. nigra) is distinguished by its large, juicy fruit and leaves that are hairy on the lower surface.