Rhubarb is a popular perennial vegetable known for its tart, edible leaf stalks, which emerge early in the spring. The plant forms a large, dense crown, producing broad, palmate leaves. Because of its vigorous growth and massive foliage, rhubarb is frequently mistaken for several other plants that share a similar appearance, especially in their early growth stages. Precise identification is necessary before any part of the plant is considered for consumption.
The Most Common Rhubarb Look-Alikes
Many plants are misidentified as rhubarb because they feature large leaves and reddish-tinged stems, two of rhubarb’s most noticeable characteristics. The most frequent culprit is Common Burdock (Arctium minus), sometimes mistakenly referred to as “Wild Rhubarb” due to its similar rosette growth pattern and imposing size. Burdock is a biennial weed that establishes a large, rhubarb-like base of foliage in its first year, causing much of the confusion among gardeners.
Another group of plants often mistaken for rhubarb are the Docks, particularly Curly Dock (Rumex crispus). Like rhubarb, which belongs to the Polygonaceae family, Dock species have large, basal leaves. These plants often appear alongside rhubarb in disturbed soils, contributing to misidentification.
Finally, Pokeweed (Phytolacca americana) is another look-alike that presents a serious safety concern. The thick, fleshy, reddish-purple stems of Pokeweed, combined with its substantial height and large leaves, can easily be mistaken for a mature rhubarb plant. This herbaceous perennial does not grow in the same tight crown formation as rhubarb.
Key Differences for Positive Identification
Petiole Structure
Petiole and stem structure help distinguish true rhubarb from its look-alikes. Rhubarb’s petioles are solid throughout, exhibiting a smooth, slightly ridged surface that is either green or shades of red. In contrast, a cross-section of a Burdock petiole will reveal that the stalk is hollow, which is a definitive way to tell the two plants apart.
Leaf Characteristics
Leaf characteristics also provide points of differentiation. Rhubarb leaves are generally smooth and glossy on both the top and underside. Burdock leaves, while large and heart-shaped, have a distinctively woolly or hairy texture on their undersides. Curly Dock leaves are easily recognized by their wavy or ruffled edges, a feature that true rhubarb leaves lack.
Growth Habit
Rhubarb grows as a single, perennial crown from which all the petioles emerge in a tight rosette close to the ground. Pokeweed, conversely, develops a thick, central, reddish stalk that branches out. Pokeweed grows more like a shrub, unlike the clumping vegetable habit of rhubarb.
Why Identification Matters: Toxicity Concerns
Accurate identification is necessary because consuming the wrong plant part or the wrong plant entirely can have serious health consequences. The leaves of true rhubarb contain high concentrations of oxalic acid, a compound that binds with calcium in the body and can cause kidney damage if ingested in large quantities. Only the stalks of the rhubarb plant are safe to eat.
Several look-alikes carry their own dangers, with Pokeweed presenting the most immediate threat. Every part of the Pokeweed plant, including its roots, berries, stems, and leaves, is toxic to humans due to the presence of saponins. Even young shoots can be harmful if not correctly handled and cooked.
While Burdock is generally not considered highly toxic, it is still not advised for culinary use in the same way as rhubarb. It is necessary to be absolutely certain of the plant’s identity before harvesting and consuming any stalk to ensure safety.