Black-eyed Susan is the fitting name given to a flower with bright yellow petals and a dark center eye.

The name black-eyed Susan is commonly used for two very different plants. The name is given to Thunbergia alata, a vining, heat-loving plant that is native to the tropical areas of East Africa.

Thunbergia alata, often grown in containers, is a late summer-blooming annual here in Pennsylvania.

Most commonly, the flowers of Rudbeckia fulgida and Rudbeckia hirta are also known as black-eyed Susans. These two species are North American native plants that have been cultivated for home gardens.

Since they are derived from North American native wildflowers, cultivated varieties of Rudbeckia bring a wealth of ecological benefits to the garden.

The halo of yellow petals provides a target and landing pad for many pollinators. A close examination of the center “eye” reveals that it is actually hundreds of individual small flowers, each holding nectar sipped by bees, small wasps, flies, butterflies and moths.

Additionally, 18 species use Rudbeckia as a host plant in Pennsylvania. Several species of birds will feast on the mature nutritious seeds of the flower heads if left intact at the end of the growing season. Save clean-up until spring.

In addition, black-eyed Susans provide a bright spot in your garden from mid to late summer. They make excellent cut flowers. Cutting them for bouquets, along with deadheading, will encourage more blossoms.

Most of the Rudbeckia varieties available in Pennsylvania are perennials. They also self-seed, so choose a spot in the garden where you will enjoy this plant long-term. They grow best in full sun but can tolerate partial shade. They prefer average, well-drained soils but can adapt to clay, alkaline or acid pH, and gravelly soils. Once established, they are heat and drought-tolerant, blooming from July into October.

Research indicates that planting a number of Rudbeckia together in a drift will attract more pollinating insects.

Even though Rudbeckia plants will self-seed once established, a gardener should not expect the best results from sowing purchased seeds directly into the ground. As with many native plants, Rudbeckia seeds germinate best if they experience a period of cold that mimics winter (stratification). This can be achieved by refrigerating the seeds before sowing indoors under lights about ten weeks before the danger of frost is past. Another way to achieve this is by sowing the seeds in a container outdoors in the fall.

Purchasing Rudbeckia transplants is probably the better option. Most greenhouses and plant nurseries in Pennsylvania will carry black-eyed Susan plants (ensure that the plant is labeled Rudbeckia). Rudbeckia can be planted in the garden in late spring or fall, about six weeks before the first frost.

Rudbeckia, having originated as North American wildflowers that thrive in disturbed landscape areas, have few serious problems. Their coarse, hairy foliage provides deer resistance. However, newly planted Rudbeckia seems to be irresistible to rabbits, Protect young plants until they are well-established in the garden.

Rudbeckia can suffer from powdery mildew. Plants can also be infected by the fungal disease Septoria leaf spot. Thinning plants and avoiding overhead watering may help alleviate the unsightly symptoms of these diseases.

There are many varieties to choose from. Keep your eyes open at nurseries and plant sales and browse catalogs for even more selections.

Consider adding this plant to your garden. You and our important pollinators will feel that you have struck gold.

“Growing Green” is contributed by Diane Dorn, Lehigh County Extension Office Staff, and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-813-6613.