Rudbeckia, also known as Black-Eyed Susan, is a genus of flowering plants in the Asteraceae family. The word “Rudbeckia” pays homage to Olof Rudbeck the Younger, an esteemed Swedish botanist from the 17th century. Rudbeckias come in many sizes, from compact varieties suitable for containers all the way up to tall, dramatic selections that command attention in larger landscapes. One of the most iconic species, Rudbeckia hirta, features radiant yellow petals encircling a dark, almost mysterious central disk – hence the common name “Black-eyed Susan.”
Leaves and Flowers
The leaves of Rudbeckias are usually deep green, lance-shaped, and coarsely textured. They form an attractive basal rosette that provides a lovely backdrop to the colorful blooms. The leaves play a vital role in photosynthesis, converting sunlight into energy to fuel the plant’s growth and flowering.
The flowers, however, are the stars of the show. Rudbeckia flowers are characterized by their distinctive appearance – a vibrant ring of golden or yellow petals encircling a dark, domed central disk. The contrast between the petals and the disk is visually striking and draws attention from afar. These flowers also serve as beacons to pollinators, attracting bees, butterflies, and even birds to partake in their nectar.
Growing and Caring For Rudbeckia
Rudbeckia is a true sun lover; they thrive in full sun to light shade, preferring at least 6 hours of direct sunlight daily. Planting them in a location with ample sunlight ensures vigorous growth, sturdy stems, and vibrant blooms. Well-draining soil is crucial for Rudbeckias. They don’t tolerate waterlogged conditions, so make sure the soil has good drainage. A slightly acidic to neutral pH (around 6.0 to 7.5) is ideal. Amending the soil with organic matter, such as compost, can improve its texture and drainage, creating an environment where Rudbeckias can flourish.
While Rudbeckias are drought-tolerant once established, consistent moisture is essential during their initial growth phase. Water newly planted Rudbeckias regularly to help them establish their root systems. Once established, water them deeply and infrequently, allowing the soil to dry out between waterings. These plants don’t require heavy fertilization. A balanced, slow-release fertilizer applied in early spring can provide all the nutrients they need for the growing season.
As Rudbeckia produces new flowers, removing the old ones can redirect the plant’s energy toward further growth and blooms. Over time, Rudbeckias can become overcrowded and develop a less vigorous growth habit. Dividing the plants every 2 to 3 years in early spring or late summer can help rejuvenate them. Dig up the plant, separate the clumps, and then replant the divisions at the appropriate spacing. While Rudbeckia is generally resistant to most pests and diseases. However, keeping an eye out for aphids, caterpillars, and powdery mildew is advisable.
Black-Eyed Susan
One of the most popular species of Rudbeckia is Rudbeckia hirta, commonly known as black-eyed Susan. This species is native to North America and is often used in wildflower meadows, cottage gardens, and as a cut flower. It produces a profusion of bright yellow or orange flowers with a characteristic dark center from mid-summer to early fall.