Yellow bluestem is a perennial, clump-forming, small, blue-gray graceful grass, with flowering stems up to 4 feet tall. Leaf blades are yellow-green, flat or folded, usually smooth. Leaf sheaths are rounded. The nodes may be smooth or with short hairs. Blooms in Missouri in late June to July, far earlier than our native bluestems. The inflorescence is silvery, reddish purple, and the length of the side branches exceeds the length of the central stem. Blooms late June through July.
Similar species: The similarly invasive Caucasian bluestem (Bothriochloa bladhii) is smaller and has blue-gray leaves; the leaf sheaths are rounded and leaf blades flat or somewhat U-shaped in cross-section; nodes are purple-tinged and may be smooth or with short hairs. Although its inflorescence is similar to yellow bluestem, the side branches are shorter than the central stem (resembling a miniature version of Johnson grass, another invasive grass, which blooms at the same time).