The black-eyed Susan (Rudbeckia hirta), a native North American plant, reproduces well from seeds and from its root system. The plant grows to a height of 3 feet and produces sunflowerlike yellow flowers that measure 3 inches across.
The seeds of the black-eyed Susan plant require cold stratification of at least three months after gathering in the fall to help ensure germination. Seeds purchased from a nursery or other retailer have already undergone cold stratification and are ready for planting.
The seeds of the black-eyed Susan plant can be planted outdoors in the garden two weeks before the last expected frost; they can also be started indoors six to eight weeks before the last expected frost. The black-eyed Susan plant freely self-seeds in the garden if the spent blossom heads are not removed. Small plants will usually begin to grow in the spring from the seeds dispersed the previous fall.
Black-eyed Susan seeds require light to germinate. If a layer of soil covers them, they will not grow. When planting the seeds, lightly sprinkle them across the soil’s surface and press down to secure them to the soil. Make sure they are not covered by soil to ensure adequate germination in five to 10 days after planting.