Reliable and low-maintenance black-eyed Susans (Rudbeckia hirta) have established themselves as a fundamental element in gardens. Their daisy-like flowers feature vibrant yellow petals surrounding a dark central disk, standing tall above wide, textured green leaves. This wildflower is indigenous to the central United States and is commonly found in natural habitats and along the roadsides of the Midwest.
Black-eyed Susans are known for their generous production of nectar and pollen, attracting various pollinators such as bumblebees, butterflies, and moths. Their self-seeding nature makes them an excellent option for lush wildflower gardens. Typically, these plants are perennials and can be sown once the last frost of spring has passed. They are likely to bloom in their first summer, although it may take two to three years for them to achieve their maximum height.
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Light
For optimal blooming, your black-eyed Susans thrive in full sunlight, although they can also tolerate some shade.
Soil
Black-eyed Susans thrive in a variety of soil types. They prefer soil that is moderately fertile and drains well, ideally with a pH level of approximately 6.8.
Water
Ensure that the plants receive adequate watering during their initial growing season to help them take root—about an inch of water weekly from rain or irrigation will suffice. After they are established, they will be able to withstand dry conditions.
Climate and Moisture Levels
This resilient summer plant thrives in warmer conditions, preferring temperatures of 60 degrees Fahrenheit and above. It adapts well to both dry and humid environments, but requires adequate air circulation to prevent the development of powdery mildew.
Fertilizer
Be cautious with the fertilizer. Black-eyed Susans thrive even in less than ideal soil conditions. A light application of compost should suffice for their needs.
Varieties of Black-Eyed Susans
The Rudbeckia genus showcases a remarkable diversity, with around 25 species that are generally resilient and low-maintenance. Among the different types of black-eyed Susans are:
- Rudbeckia hirta ‘Becky’ is a small, compact cultivar.
- Rudbeckia hirta ‘Maya’ bears a striking resemblance to a lofty marigold.
- Rudbeckia hirta ‘Cherry Brandy’ features blossoms in shades of red to maroon, surrounding deep-colored central cones.
- Rudbeckia fulgida ‘Goldsturm’ features flowers resembling daisies, characterized by a central cone that is brown or black in color.
- Rudbeckia laciniata ‘Autumn Sun’ is a variety that produces vibrant golden yellow flowers, typically blooming from mid to late summer.
- Rudbeckia hirta ‘Prairie Sun’ showcases vibrant orange petals adorned with yellow edges, surrounding a green center.
- Rudbeckia hirta ‘Indian Summer’ features vibrant yellow blooms and can grow to a height of 3 to 4 feet.
- Rudbeckia hirta ‘Toto Rustic’ showcases warm autumn colors, while the golden ‘Toto’ and the soft ‘Toto Lemon’ varieties also reach a height of approximately 1 foot.
Pruning
Black-eyed Susans are simple to grow, adapt easily to their surroundings, and need minimal care aside from removing spent blooms. By consistently deadheading the wilted flowers, you can extend the blooming period. It’s also beneficial to leave the final blooms of the season on the plants, as they will develop seed heads that provide food for birds during the winter months. Additionally, you can expect a fair amount of self-seeding, which can be advantageous.
Black-eyed Susans are excellent for floral arrangements. Their seed heads are durable and add visual appeal to displays. This fast-growing variety of Rudbeckia is perhaps the most recognized, featuring daisy-like blooms and prominent seed heads. Additionally, it possesses rough, hairy foliage, which, while not the most appealing trait, serves to deter pests.
Propagating
Rudbeckia hirta is a perennial plant with a shorter lifespan that may not mature enough to create extensive, thick clusters. However, if it does reach that stage, it can be propagated by division in early spring, as new shoots emerge, or in the fall, after the blooming period has concluded.
- Use a shovel to carefully remove the whole plant from the soil. Then, separate it into two or more sections with the help of pruners or a spade.
- Transplant each part to a different spot and ensure it remains adequately watered until you observe new growth in a few weeks.
As black-eyed Susans have a tendency to self-seed, you could find new plants emerging in your flower beds next year.
A Guide to Cultivating Black-Eyed Susans from Seeds
To gain an advantage for the upcoming growing season, begin cultivating black-eyed Susans indoors from seeds approximately 10 weeks prior to the anticipated last frost. Here’s the process for growing them from seeds in containers:
- Sow seeds at a depth of 1/4 inch in trays or pots that contain a damp seed starting mix. For optimal germination of perennial varieties, it’s beneficial to store the seed containers in the refrigerator or a cool environment for four weeks following planting. Once this period is over, the soil temperature should be elevated to encourage germination. Expect seeds to sprout within a timeframe of 7 to 21 days.
- Acclimate the seedlings to outdoor conditions prior to transplanting them. Ensure that the risk of frost has completely subsided before moving them outside.
Black-eyed Susans can be sown directly in the garden when the daytime temperatures consistently reach about 70 degrees. Here’s the method for direct seeding:
- Sow the seeds, lightly cover them with soil, and ensure they are thoroughly watered. Maintain the soil’s moisture.
- Space thin seedlings 6-12 inches apart for dwarf types and 18-30 inches apart for larger varieties.
If you prefer not to grow your own seeds, you can buy seedlings and plants and then transplant them.
Frequent Insects and Plant Illnesses
Black-eyed Susan generally remains unaffected by major pests and diseases. Nonetheless, it may encounter problems with aphids, spider mites, snails, and slugs. These pests can be removed by spraying them with water or using a mild insecticide. While young, tender shoots may be susceptible to nibbling, mature plants develop coarse, hairy leaves that deter deer.
Septoria and angular leaf spots are fungal infections that create dark spots on leaves and stems. To promote healthy air circulation, ensure there is sufficient space between plants, and take care not to wet the leaves during watering, as this can facilitate the spread of the fungi. Disposing of infected leaves in the trash rather than composting them is an effective way to limit the spread of the disease.
Tips for Encouraging Black-Eyed Susans to Flower
Flowering Periods
Black-eyed Susan usually flowers from late spring to early summer, with its blooming period spanning from March to November, and it reaches its fullest bloom during July and August.
How do Black-Eyed Susan flowers appear and what fragrance do they emit?
Black-eyed Susans are typically seen in a vibrant yellow hue, featuring rich yellow-orange petals surrounding a dark brown central disc. Their fragrance is a delightful blend of sweetness and spice, reminiscent of anise to some.
Ways to Promote Increased Flowering
Black-eyed Susans thrive in full sunlight for optimal blooming. If they are overshadowed by nearby trees or shrubs, a bit of pruning could help increase their exposure to sunlight. Certain perennial types might take until their second year to produce flowers. Additionally, an excess of nitrogen can hinder blooming, leading to abundant leaves but a lack of flowers. If you choose to fertilize, it’s best to select a formula rich in phosphorus to encourage blooming, as these plants often flourish without any fertilization.
Frequent Issues Encountered with Black-Eyed Susans
Powdery mildew may impact leaves in warm, humid environments. To reduce this risk, consider planting in areas with full sunlight and spacing the plants to enhance air flow.
What are some excellent perennial plants to pair with black-eyed Susans?
Black-eyed Susans and various Rudbeckia species serve as excellent companions to blue and purple blooms, such as Russian sage and Veronica, or can be beautifully combined with other jewel-toned plants, including sedum ‘Autumn Joy’, purple coneflower, and New England asters.
What steps should you take to prepare black-eyed Susans for winter?
Black-eyed Susans can withstand winter conditions as far as USDA zone 3, eliminating the need for winter protection. However, the plants thrive when their stems are trimmed in the autumn and are topped with a generous layer of mulch.
Are black-eyed Susans safe for pets? Black-eyed Susan is safe for pets and is not included in the ASPCA’s list of toxic plants.
