Tall thistle is a biennial that grows from 3 to 8 feet tall. The stems are light green and freely branched (Figure 22). Most leaves are lanceolate or long-ovate, tapered at the end and not as deeply lobed as field thistle leaves. The leaves of tall thistle more closely resemble dandelion leaves, compared to the oak-leaf shape of field thistle (Figure 23). The leaves are green on top, densely pubescent and white beneath, and 4 to 11 inches long and 1.5 to 4 inches wide. Leaves near the base are largest and gradually are smaller and more elliptical toward the top. The leaves are alternate and toothed or with weak spines. Rosette leaves are similar to the lower leaves of the bolted plant, large and only slightly lobed.