Right when August arrives and the days are hottest, black-eyed Susans (Rudbeckia) show up in flower gardens and open fields, lighting them up like rays of sunshine. If any plant could be the poster child of late summer, it would be this one. The brightly colored flowers in cheery shades of lemon-yellow, orange, and gold bloom for weeks with minimal care. They also attract a lot of different pollinators, which makes the summer garden even more colorful and lively.
Suggested Paraphrasing: In 2008, the National Garden Bureau put black-eyed Susans in the spotlight by declaring Rudbeckia the plant of the year. This led to the development of an impressive array of garden cultivars in a complete gamut of heights, colors, and forms. These new-generation Susies offer greater flair and versatility, making them suitable for settings ranging from prairie-style plots to urban gardens.
Types of Black-Eyed Susan
Here are some of the most common types of black-eyed Susans out there. Not all of them are just golden yellow in color.
- Rudbeckia hirta, ‘Black-Eyed Susan’, ‘Brown-Eyed Susan’, ‘Lazy Susan’: this is the most widespread of the rudbeckia and the Maryland State flower. Annual, biennial, or perennial depending on the cultivar.
- Rudbeckia fulgida, ‘Rudbeckia Goldsturm’, ‘Orange Coneflower’, ‘Perennial Coneflower’: seven cultivars, two of which have received the Royal Horticultural Society’s award of garden merit. Tall stems with gold-petaled flowers with a pronounced central cone.
- Rudbeckia californica, ‘California Coneflower’: Native in meadows and river bottoms of northern California. Perennial wildflowers that grow taller stems about 1 to 2 meters tall. Cylindrical cone surrounded by bright yellow petals.
- Rudbeckia triloba, ‘Browneyed Susan’, ‘Brown-Eyed Susan’: More commonly seen in fields or along roadsides. A more expansive mat of smaller flowers. Leaves grow in triads.
- Rudbeckia hirta ‘Cherokee Sunset’: one of those dwarf varieties of double-flowered Rudbeckia with petals the color of the setting sun. Sometimes bicolor shades of yellow, orange, red, bronze, and mahogany.
- Rudbeckia hirta ‘Double Gold’: a thick ray of golden petals that seems almost double in its density. Reaches up to 2 feet tall.
- Rudbeckia hirta ‘Toto Lemon’: plentiful blooms produce on these densely-petaled flowers. Each petal is short and blunt compared to other coneflower species.
- Rudbeckia ‘Denver Daisy’: flowers have dense, compact petals with dark brown-dabbed centers. Winner of 2010 American Garden Award.
- Climbing Black-Eyed Susan: unique among this list. Tender perennial black-eyed Susan vine that is native to Eastern Africa. Characteristic of black-eyed Suzie with a vine growth pattern.
HOW TO PLANT
When to plant:
Black-eyed Susans are easy to grow from seed and there is a much broader selection of cultivars to choose from if you do. You can start the seeds indoors in early spring about 10 weeks before your climate’s last frost date or sow them directly in the garden in spring or summer. Perennial varieties can be sown from seed or transplanted in fall or early spring. The soil temperature should be about 70° F for the best seed germination.
Where to plant:
Rudbeckia will do best in a sunny location with well-drained soil. If the location is hot and humid, choose a spot where the plants will get good air circulation to prevent powdery mildew.
Sowing directly in the garden:
Plant your seeds by scattering them and lightly pressing them into the soil. Water them regularly to keep the seedbed moist. As the seedlings grow, thin them out so that they are 6 to 12 inches apart for dwarf varieties and annuals, and 18 to 30 inches apart for perennials, depending on how large the mature plant will be. Water your plants thoroughly until they are well-rooted and established, at which point they will be able to tolerate drier conditions.
Sowing seed indoors:
After you have sowed your seeds indoors, water them according to the directions on the seed packet. Put them in a sunny spot, like a windowsill or under fluorescent plant lights. Once the seedlings have started to grow, keep them in a cold frame or another sheltered spot outside for a week so they can get used to the outdoors.
Pruning
Prune the first yellow flowers and seed heads to increase the bloom period. Deadhead spent blossoms to prevent automatic self-seeding. Allow them to reseed in the bed, but other species of plants and younger black-eyed Susans may get crowded out. Give coneflowers plenty of room for good air circulation. Prune the stems back after they have finished flowering to try to encourage another flush of blossoms.
Repotting Black-Eyed Susans
To repot a root cluster, ensure you have a well-draining potting mix that is rich in organic matter. Place the root cluster into the medium at the same height as the original plant was buried. Fill in under and around the root mass with more potting soil. Be sure that you have a larger pot than you need because the black-eyed Susan will spread to fill your container during the growing season.
Black-Eyed Susan Propagation
There are two ways to propagate these lovely flowering plants. Seeds can be sown directly or into pots (see the Planting section above), or you can propagate by dividing a plant in spring or fall, before or after the flowers bloom. To divide and plant black-eyed Susan, first scoop out the soil around the base of the plant to establish how wide the root mass is. Then dig 6 to 10 inches out from the base of the plant on all sides. Slide a trowel, transplanter, or shovel in underneath the root mass and remove it, being careful not to damage the roots. Shake or dust off excess dirt. Finally, gently tease apart the root mass, or cut it with a sterilized knife. Plant 3 to 5 tuberous roots that contain both thick tubers and smaller roots with each clump. Divide your perennial plants every 3-5 years to keep them from becoming overcrowded.
GROWING TIPS
Like most wildflowers, black-eyed Susans are remarkably carefree, drought-tolerant, and disease resistant. Even so, here are some steps you can take to prolong their bloom time and keep them healthy:
- To extend the flowering period, deadhead your plants by pinching off the blooms at the base of the stem. You can cut also cut back black-eyed Susans after they flower to encourage a second surge of blooms later in the fall.
- If you want to attract birds to your garden, leave a few flower heads on your plants and let them to go to seed. You’ll also be rewarded by new seedlings sprouting up in the garden the following spring.
- Because Rudbeckia are zealous self-seeders, you may end up with more plants than you bargained for. If your plot becomes overcrowded, remove or transplant the extras.
- You can propagate perennial black-eyed Susans by division in early spring, just as growth begins to develop, or in the fall after they finish flowering. Simply dig up the root ball and cut it with a sharp knife, making sure each division has roots. Replant the divisions about 12 to 18 inches apart.
- Black-eyed Susans don’t like water lingering on their foliage, which can result in powdery mildew. Be sure to maintain adequate spacing between plants and water at soil level rather than watering from above.
PLANT AND SEED SOURCES
GOOD COMPANIONS
Black-eyed Susans grow alongside bee balm.
Although the bright, sunny flowers and dark center cones of black-eyed Susans create a striking color contrast on their own, these versatile plants pair beautifully in the garden with other summer- and fall-blooming perennials and annuals. Try some of these high-impact looks:
- Combine them with the cool blues and purples of Russian sage (Perovskia atriplicifolia), fall-blooming asters, tall verbena (Verbena bonariensis), salvia, and giant hyssop (Agastache ‘Blue Fortune’).
- Heat things up by grouping them with other warm-colored bloomers such as yarrow (Achillea ‘Terracotta’), zinnias, and tiger lily (Lilium lancifolium).
- If you go gaga for daisies, plant a cutting garden of daisies and their look-alikes, filling it with black-eyed Susans, purple coneflowers (Echinacea purpurea), shasta daisies (Leucanthemum xsuperbum), and sunflowers (Helianthus).
- Attract a diversity of butterflies and bees by intermingling black-eyed Susans with other pollinator-friendly perennials of various colors, heights, and textures. Good choices include Sedum ‘Autumn Charm’, showy goldenrod (Solidago speciosa), Joe Pye weed (Eutrochium purpureum), bee balm (Monarda), blazing star (Liatris spicata), and butterfly weed (Asclepias tuberosa).
- Because Rudbeckia are native plants, they are a natural addition to prairie-style gardens and harmonize well with large drifts of ornamental grasses, such as switchgrass (Panicum virgatum), maiden grass (Miscanthus sinensis), little bluestem (Andropogon scoparius), and fountain grass (Pennisetum alopecuroides).
Troubleshooting
Some of the main issues that black-eyed Susans can face include powdery mildew, rust, and aphids. Powdery mildew is a fungus that can attack black-eyed Susans, causing the leaves to turn white and eventually die. Rust is another fungal disease that can cause the leaves to turn brown and fall off. Aphids are tiny insects that can suck the nutrients out of the plants, causing them to weaken and eventually die. To avoid these issues, make sure to plant your black-eyed Susans in well-drained soil and in an area that gets plenty of sunlight. Also, be sure to water them regularly and fertilize them twice a year. If you see any signs of disease, be sure to treat the plants immediately.
Growing Problems
If you water your black-eyed Susan too much in a medium that doesn’t drain well, you can kill it. Make sure the area where you’re growing black-eyed susans has good drainage to produce blooms. Black-eyed susans can also take over your garden if you’re not careful. To prevent this, remove as many blooms as possible during the growing season, and prevent them from reseeding the following year.
Pests
If you don’t want aphids ruining your plants, spray them with neem oil. This will deter the aphids and help prevent them from sucking the sap out of your plants.
Neem oil prevents the eggs of cabbage worms from hatching and Pyrethrins are effective against both aphids and cabbage worms.
If you want to use pyrethrins in your garden, it’s best to spray in the late afternoon or early evening. This is because cabbage moths are active at night and aphids are at rest at this time. This gives the pyrethrins time to dry on the plant before butterflies become active again.
Diseases
Powdery mildew is a fungal disease that creates white patchy spots on the leaves of your plant. If your plant is infected with powdery mildew, you should remove and destroy the affected flower, seed, and leaf parts of the plant. You can also prevent the disease from spreading by spraying all plant surfaces thoroughly with neem oil. If most of the plant is mildewed, you can try to wipe out the mildew by spraying neem oil on the plant every few days. However, this may or may not be effective. If treatment is not effective, you should remove the entire plant and destroy it.
It may be hard to get rid of downy mildew, and you may need to use a liquid copper fungicide. The liquid copper fungicide will not only take care of mildew, but also some leaf spot diseases and downy mildew.
Black-eyed Susan is also susceptible to leaf spot diseases in the garden. While the liquid copper fungicide mentioned above will help with some of the leaf spot issues, it doesn’t work on the most damaging leaf spot for its species. Septoria leaf spot is caused by the plant pathogen Septoria rudbeckiae, and it causes dark, almost black spotting to the leaves of your plant. To combat this particular leaf spot, you’ll need a fungicide that contains the active ingredient chlorothalonil.
The pathogen that causes verticillium wilt is soil-borne and cannot be cured. If you have plants in your garden that are affected by this disease, you should remove them and treat the soil with a fungicide to kill the pathogen. You should also not sow seeds from an infected plant in your garden.
