How to Plant, Grow, and Care for Black-eyed Susans
Black-eyed Susans (Rudbeckia hirta and other species) are native to North America and one of the most popular wildflowers grown. It has become naturalized in Zones 3 to 9. Black-eyed Susan, aka Gloriosa daisy, blooms from June to September, often blanketing open fields with their golden-yellow beauty, often surprising the passerby
About Black-eyed Susans
A member of the aster family, Asteraceae, the “black eye” is named for the dark, brown-purple centers of its daisy-like flower head. The plants can grow to over 3 feet tall, with leaves of 6 inches, stalks over 8 inches long, and flowers with a diameter of 2 to 3 inches. They are outstanding cut flowers that also do well in borders or containers.
Butterflies, bees, and other insects are attracted to the flowers for the nectar. As they drink the nectar, they move pollen from one plant to another, causing it to grow seeds that can move about easily with the wind. Note that they can be territorial in that they tend to squash out other flowers growing near them.
Some Black-eyed Susans are susceptible to leaf diseases. Some newer varieties are resistant to these diseases.
Black-eyed Susan thrives in full sunshine. It tolerates partial sun, but it will not bloom as reliably. Black-eyed Susan prefers rich, well-draining soil, although plants will tolerate low fertility.
When to Plant Black-eyed Susan
If direct-seeding, plant in moist, well-draining, warm (70º to 75ºF) soil.
Indoors, sow seeds 8 to 10 weeks before the last frost. Germination takes 7 to 10 days.
In many parts of North America, the planting period is March to May.
How to Plant Black-eyed Susan
Cover seed lightly with soil. Sunlight is required for germination
Set seeds and plants close to deter spreading, or farther apart for a border and to prevent the spread of disease.
It’s best if soil is fertile (not poor), though they can tolerate tough conditions.
Black-eyed Susans generally grow between 1 and 3 feet tall (though they can grow taller) and can spread between 12 to 18 inches, so plant seeds closer to prevent lots of spreading or plant further apart to make a nice border.
Remove faded or dead flowers to prolong blooming. Removing spend flowers and seed heads reduces self-sowing. Check plants regularly to see if they need watering. Make sure they don’t dry out, but also avoid excess moisture on leaves, which can encourage disease (provide plants with proper spacing).
Remove dead plant debris in spring to reduce the risk of infection. Divide perennial types every 3 to 4 years to ensure healthy plants and to prevent excessive spreading.
Cutting back black-eyed Susan after flowering may result in a second, smaller bloom in late fall.
Leave some dried seed heads on the plants in the fall to attract birds.
After the first season, black-eyed Susans can reseed themselves.
To prevent underground spread, dig up rhizomes, making certain to remove the entire piece of root. Even a small section of rhizome can produce another plant.
‘Becky Mixed’, which offers a variety of colors for your garden, such as lemon-yellow, golden-yellow, dark red, and reddish-brown.
‘Sonora’, which has bright yellow flowers.
‘Toto’, which is a dwarf type and ideal for containers.
Cut flowers for display just before buds completely open. Use large blooms as centerpieces and smaller ones as accents. Change the water every day to kept them fresh. Vase lit is 8 to 10 days.