Black-Eyed Susan (Rudbeckia hirta) is a native North American plant known for its bright yellow, daisy-like petals surrounding a dark central cone. It is widely cultivated as a biennial or short-lived perennial that readily self-seeds in gardens and meadows. Identifying this plant in its earliest stages, before the familiar flowers appear, requires attention to the subtle but specific features of its vegetative growth.
The Seedling Stage
The initial appearance of the Black-Eyed Susan plant begins with the cotyledons, which are the first, temporary seed leaves that emerge from the soil. These first leaves are typically small, oval, and possess smooth margins, bearing little resemblance to the mature foliage.
The first set of true leaves soon follows, offering the first identifiable clues to the plant’s identity. These tiny leaves are simple, oval, and characterized by a prominent midvein. Importantly, these emerging true leaves will be covered in fine, short hairs, providing a slightly fuzzy texture.
Developing the Basal Rosette
The plant soon develops into a basal rosette, a dense, low-growing cluster of leaves radiating from a central crown at ground level. For a biennial Black-Eyed Susan, the rosette is the primary form the plant takes, sometimes for an entire growing season, before it stores enough energy to flower.
The leaves forming this rosette are larger than the initial true leaves, becoming lance-shaped or lance-elliptic. A defining feature is the coarse, stiff, bristly hairs that densely cover the leaves and the petioles (leaf stalks). This gives the entire rosette a rough, abrasive feel, which is reflected in the plant’s species name, hirta, meaning hairy. These deep green leaves typically exhibit an entire, untoothed margin.
Early Growth Look-Alikes
The Black-Eyed Susan rosette can be easily mistaken for other common garden plants or weeds in its early stages due to the similar low-growing, clustered growth pattern. Many members of the daisy family (Asteraceae), such as young coneflowers, have similar initial leaf forms. However, the unique texture of Rudbeckia hirta is the key differentiator.
The distinctive coarse, bristly hairs covering the leaves help distinguish the Black-Eyed Susan from smooth-leaved rosette weeds like common dandelion. Dandelion leaves are generally smooth and lack the dense hairiness found on Rudbeckia hirta. While other plants may possess some hairiness, the specific roughness and stiffness of the hairs on the Black-Eyed Susan rosette are reliable for identification before flowering.
Transition to Flowering
The transition from the basal rosette phase to flowering is marked by the process of stem elongation, often called bolting. This typically occurs in late spring or early summer after the plant has successfully stored energy. A central, upright stem emerges from the center of the basal rosette, rapidly growing upward.
This flowering stem is stout, often grooved, and covered in the same kind of stiff, spreading hairs as the basal leaves. Leaves along the stem are alternately arranged and become progressively shorter-stalked or even stalkless as they ascend the plant. The top of the stem culminates in a single, terminal flower bud, signaling the imminent appearance of the iconic golden-yellow ray flowers.