Rudbeckia hirta and other species
- Black-eyed Susans when the soil temperature has reached 70 degrees F for best seed germination. In many parts of North America, the planting period is March to May. The flower will flower June to September. Germination takes 7 to 30 days.
- Plant seeds in moist, well-drained soil.
- These hearty flowers really enjoy the Sun. They prefer full sun, though they'll grow in partial sun.
- Sow by seed in loosely covered soil.
- 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.
- Check your plants regularly to see if they need watering. Make sure they don't dry out.
- Divide perennial types every 3 to 4 years to ensure healthy plants and to prevent excessive spreading.
- Be sure to remove faded/dead flowers to prolong blooming.
- You can cut back black-eyed Susans after they flower and a second, smaller bloom may occur in late fall.
After the first season, black-eyed susans can reseed themselves!