Common Mullein (Verbascum thapsus) and Lamb’s Ear (Stachys byzantina) are often confused due to their similar soft, fuzzy, grayish-green foliage. Both species use a dense covering of fine hairs, called trichomes, to protect themselves from harsh sun and reduce water loss, creating their characteristic texture. However, they belong to different botanical families and exhibit distinct growth patterns and structures. This article provides clear visual keys to distinguish between these two species upon closer inspection.
Distinguishing Characteristics of the Leaves and Texture
The basal leaves of Mullein and Lamb’s Ear offer the first major distinction. Common Mullein leaves are significantly larger, often reaching 12 inches or more, and are generally thicker and broader. Their texture is frequently described as dense felt or wool, due to an extremely thick layer of yellowish-green or bright green trichomes.
In contrast, Lamb’s Ear leaves are noticeably smaller, typically two to six inches long, and are more oblong or spoon-shaped. The fuzz on Lamb’s Ear is softer, like velvet, and the leaves present a more silvery or gray-white hue. Mullein leaves also possess slightly scalloped or wavy edges, while Lamb’s Ear leaves are smoother along the margin. Mullein forms a thick basal rosette sitting tightly on the ground, whereas Lamb’s Ear leaves are arranged in a loose, clumping mound.
Differences in Growth Habit and Stem Structure
The overall structure and life cycle provide the clearest identification marker. Common Mullein is a biennial plant, meaning it lives for two years. The first year is spent as a large, low-to-the-ground rosette of leaves, storing energy for the next season.
During its second year, Mullein uses this stored energy to send up a massive, single, rigid central flower stalk, a process called bolting. This stalk can easily reach heights of six to eight feet, or sometimes taller. The flowering stalk is also densely fuzzy and has smaller leaves alternating up its length.
Lamb’s Ear, conversely, is a perennial plant that remains low-growing, often used as a groundcover. It spreads horizontally via runners or stolons, forming a dense, silvery mat that expands outward. Its flower stems are much shorter, usually reaching only 12 to 24 inches high, and are far less rigid than the central spire of Mullein.
Comparing Flower Spikes and Seed Pods
When the plants mature, their reproductive structures offer a clear visual difference. Mullein develops a very tall, dense flower spike covered in numerous small, five-petaled flowers that are almost always bright or pale yellow.
These yellow flowers bloom sequentially, starting from the bottom of the stalk and moving upward over weeks or months. After flowering, the stalk dries out, leaving behind a rigid column packed tightly with small, rounded seed capsules.
Lamb’s Ear produces shorter, less conspicuous flower stems, usually topping out under two feet. The flowers are generally small, pinkish-purple, or sometimes white, and are arranged in whorled clusters along the upper part of the stem. These clusters are often partially hidden by woolly bracts, making the overall display less showy. The resulting seed heads are also less noticeable and dense than the numerous capsules found along the dead Mullein stalk.