Wild marijuana, often called feral cannabis or “ditch weed,” is a descendant of industrial hemp or abandoned agricultural strains that have reverted to growing on their own. These plants are typically low in the psychoactive compound THC and are characterized by a fibrous structure, having been historically cultivated for their stalks rather than their flowers. They often exhibit a less manicured, more spindly appearance than cultivated relatives.
Key Characteristics of Wild Cannabis Leaves
The foliage of wild cannabis is perhaps its most recognizable feature, defined by its compound, palmate structure. This means the leaf is composed of several smaller leaflets that radiate outward from a central point at the end of a long leafstalk, much like the fingers on a hand. The number of leaflets can vary, but mature plants typically display leaves with an odd number, most often five to seven, though some can have up to thirteen leaflets depending on the plant’s age and environmental conditions.
A defining characteristic is the serrated edge of each leaflet, giving the leaf a distinctly jagged, toothed margin. This serration is not uniform; a central vein extends toward the tip of each tooth, but its origin is lower down the central vein of the leaflet, often opposite the second notch. The color is generally a vibrant to medium green, and the texture is slightly rough due to the presence of fine hairs, known as trichomes, on the surface.
Stem Structure and Growth Habit
The central stalk is rigid, cylindrical, and highly fibrous, a remnant of its industrial hemp lineage. It provides structural support and transports water and nutrients. As the plant matures, the pith, the soft tissue at the core of the stem, often becomes hollow, contributing to the plant’s lightweight but sturdy structure.
Feral plants typically exhibit a tall, somewhat spindly growth habit, often reaching heights of six to ten feet when growing unchecked in an open environment. This is because they grow quickly, competing for light without the pruning or training common in cultivated varieties. The branches and leaves emerge from nodes along the stem, with the spacing between these nodes, or internodes, affecting the plant’s overall density.
The leaf and branch arrangement changes as the plant grows. Lower down the stem, the leaves and branches sprout directly opposite each other at each node. As the plant gains height and matures, this arrangement transitions to an alternate pattern, with only one leaf or branch emerging per node, alternating sides as it progresses upward. Wild cannabis thrives in disturbed soils, often appearing along roadsides, in fields, or in floodplains—locations that gave rise to the common name “ditch weed.”
Common Plants Mistaken for Wild Marijuana
Many plants share the palmate leaf structure, leading to frequent misidentification. The Japanese Maple, particularly young saplings, is a common look-alike because its leaves also have a palmate shape with serrated edges. However, the Maple leaf has fewer, broader lobes that typically turn red or purple later in the season, unlike the consistently green and narrower leaflets of cannabis.
Another frequently confused species is the Spider Flower, or Cleome, which also displays compound leaves. Cleome leaves are typically stickier and produce showy white or pink flowers that grow in large clusters.
Kenaf (Hibiscus cannabinus) is also mistaken due to its similar star-like leaf pattern and fibrous stalk. Kenaf leaves, however, are often more deeply lobed and divided differently than the distinct leaflets of cannabis, and the plant produces a large, hibiscus-like flower.
The Chaste Tree (Vitex agnus-castus) is another contender, sharing the five-leaflet palmate arrangement, but its leaflets are notably smoother and lack the characteristic serrated margins of wild cannabis.