Black-Eyed Susan (Rudbeckia hirta) is a popular North American wildflower, often cultivated for its bright, long-lasting blooms. For gardeners who sow seeds directly, accurately identifying the delicate young plants is important for successful cultivation, especially for thinning crowded sprouts or preventing accidental weeding. Recognizing the seedling’s distinct features ensures the desired plants thrive while unwanted species are removed early.
The First Leaves: Cotyledon Appearance
The initial leaves to emerge from the seed, known as cotyledons, do not resemble the mature Black-Eyed Susan foliage and are temporary structures. These first leaves are typically small, appearing as a pair of simple, rounded or slightly oval shapes just above the soil line. They are often a smooth, pale green color and may have a slightly waxy or velvety texture, lacking the roughness of the later leaves.
Cotyledons are generally uniform in size and shape, a trait shared by many different species of seedlings, making them unreliable for definitive identification alone. The initial stem connecting the cotyledons to the soil is usually thin and smooth. As the seedling develops, the cotyledons will eventually shrivel and fall off after the true leaves have fully emerged.
Identifying the True Leaves
The true leaves are the definitive characteristic for identifying Black-Eyed Susan seedlings. These leaves grow from the center of the cotyledons and are the first to display the traits of the mature plant. The true leaves are notably covered in short, stiff hairs, a feature reflected in the species name hirta, which is Latin for “hairy.”
This hairiness gives the leaves a rough, almost abrasive texture, distinguishing them from smoother weed seedlings. The shape of these early true leaves is typically ovate or lanceolate, unlike the rounded cotyledons. They emerge in an opposite arrangement, forming a tiny rosette close to the ground, and their color is a medium-to-deep green. The combination of the specific shape and the dense, coarse hair is the reliable signature of the young Black-Eyed Susan plant.
Common Seedling Look-Alikes
Many common garden weeds and other flowers can be mistaken for Black-Eyed Susan seedlings, leading to accidental removal. For instance, Horseweed (Conyza canadensis) seedlings also have a rosette growth habit and fine hairs. However, Horseweed leaves are more narrowly lance-shaped, and the hairs are much softer and less coarse than the distinct, bristly trichomes of Rudbeckia hirta.
Confusion can also occur with other plants in the Asteraceae family, such as Echinacea purpurea. While Echinacea seedlings have a coarse texture, their leaves often emerge with a slightly more toothed or serrated edge, whereas the first true Rudbeckia leaves are often entire. Gardeners should also observe the stems; Rudbeckia hirta stems are covered in the characteristic coarse hair, while many look-alikes may have smooth or sparsely hairy stems.