Wild hemp, a variant of Cannabis sativa, grows without cultivation and has adapted to various ecosystems over time.
Physical Characteristics of Wild Hemp
Wild hemp plants have distinct physical features that aid identification.
Overall Plant Structure
Wild hemp typically grows tall and slender, often reaching 3 to 15 feet. It grows erect with little lower branching, giving it a tall, cane-like appearance that grows vertically rather than spreading horizontally.
Leaves
The leaves of wild hemp are palmately compound, radiating from a central point. Each leaf usually consists of 3 to 9 leaflets that are narrowly ovate or linear to narrowly elliptic, tapering to a point at each end. Leaflets are typically dark green, may have sparse hairs, and have coarsely serrated edges. Lower leaves often have long petioles, while upper leaves are nearly sessile.
Stems
Wild hemp plants have stout, light green, canelike stems that are hollow, except at the tip and base. New growth may appear hairy, becoming less so with age. Stem texture and diameter can vary.
Flowers
Wild hemp is dioecious, with separate male and female plants. Male plants produce small, greenish flowers that can turn cream or pale yellow as they mature. Male flowers are about 1/8 inch across, with 5 sepals and 5 stamens, loosely clustered in panicles up to 1 foot long. Female plants produce short, green, axillary spikes of flowers, about 1 inch long, covered with glandular hairs. Each female flower is small, about 1/8 inch long, with a single sepal, an ovary, and two styles, lacking petals.
Seeds
Wild hemp seeds are contained within achenes. Mature seeds have a tough outer shell, ranging from dark to light gray, sometimes with tiger-like streaks. These seeds are typically small, around 2-3 mm across, and are found hidden under leafy parts. Ripe seeds feel tough when pressed.
How to Differentiate Wild Hemp from Marijuana
Distinguishing wild hemp from marijuana is challenging due to their visual similarities as Cannabis sativa varieties. Their primary difference lies in their chemical composition, specifically delta-9 tetrahydrocannabinol (THC) concentration. Wild hemp contains very low THC levels, typically less than 0.3% on a dry-weight basis, meaning it does not produce intoxicating effects.
Marijuana is cultivated for higher THC levels, often 15% to 30% or more. Visually, marijuana plants are often shorter and bushier, maximizing flower production, and may appear darker green with a stronger odor. Hemp plants, especially those grown for fiber, are typically taller and skinnier with less branching, focusing on stalk development.
Despite visual tendencies, definitive identification requires laboratory THC testing. While sticky, glandular trichomes are more pronounced on marijuana flowers, relying solely on appearance is unreliable for legal or recreational purposes.
Where Wild Hemp is Commonly Found
Wild hemp, or “ditch weed,” grows naturally in various disturbed habitats. Its North American presence largely stems from World War II industrial hemp cultivation (“Hemp for Victory” campaign), after which feral populations re-seeded and continue to thrive where cultivation ceased.
Wild hemp is commonly found in the American Midwest, especially in states like Indiana, Nebraska, Kansas, Iowa, and Missouri. It prefers continental climates with cold winters and rich, deep soils, often in former agricultural lands. Habitats include floodplain woodlands, low-lying fields, weedy meadows, fence rows, and roadside ditches. This resilient plant tolerates moist conditions and various soil types, thriving in fertile loamy soil.