Black-Eyed Susans have deep, wide root systems, so they aren't ideal for growing in pots or planters. However, growing these perennials in containers can be achieved! Use a large pot, at least one gallon in size, for each plant, and make sure the container has excellent drainage. Moist potting soil makes a good medium for planting Black-Eyed Susans. Place the containers in a sunny location, and water regularly, as potted plants tend to dry out more quickly than plants set in the ground.