This wildflower is native to the central United States and can be seen growing in natural areas and along roadsides in the Midwest. Its ability to self-seed makes it a great choice for abundant wildflower gardens. You can plant it after the last frost in spring. It will flower in its first summer although it can take two to three years to reach full height.
There is a great deal of variety within the Rudbeckia genus, and most of the 25 species are true workhorses with very few problems. Fast-growing black-eyed Susan is easily the most commonly known Rudbeckia, with its daisy-like flowers with large seed heads. It also has the scratchy, hairy leaves that are characteristic of its genus (this may not be one of its best features, but it does help keep pests away).
Black-eyed Susans are easy to establish, they naturalize well, and require little maintenance other than deadheading. Regular deadheading of the faded flowers keeps the plants in bloom longer. You can let the last flowers of the season remain on the plants to form seed heads that will feed the birds through the winter. You will also get a good deal of self-seeding, which might not be a bad thing.
Black-eyed Susans make great cut flowers. The seed heads hold up well, too, and look attractive in arrangements.
You will get the best flowering from your black-eyed Susans in full sun, but they can handle partial shade.
Black-eyed Susans are not particular about soil. They do best in soil that is not too rich and is well-drained, with a pH around 6.8.
Keep the plants well-watered - an inch per week through rainfall or irrigation is sufficient. Once established, they will be drought-resistant.
As a tough summer performer, this plant likes warmer temperatures of 15 degrees Celsius and more. It handles both drought and humidity well, but it does need good air circulation to avoid powdery mildew.
Go easy on the fertilizer. Black-eyed Susans grow even in poor, infertile soil.1 A side dressing of compost should be all they will need.
Black-eyed Susan is rarely bothered by serious pests and diseases. Septoria or angular leaf spots are two fungal diseases that form black spots on the leaves and stems. Provide good air circulation by leaving ample space between plants, and avoid getting the leaves wet when watering as that can spread the fungi. Removing and throwing infected leaves in the trash instead of composting helps to contain the spread.
|Botanical Name||Rudbeckia hirta|
|Plant Type||Short-lived perennial, annual|
|Mature Height||61-91 CM (24"-36")|
|Mature Width||30-61 CM (12"-24")|
|Soil Type||Moist, well-drained|
|Soil pH||Acidic, Neutral|
|Bloom Time||Summer, Fall|