Learn how to grow rudbeckia, a low-maintenance flower recognizable for its vibrant yellow and orange petals with a striking black center. Rudbeckias are easy to grow and care for, making them a perfect choice for those new to gardening or looking for a hassle-free addition to their garden. I love planting rudbeckia at the end of my raised beds to attract butterflies, bees, and other beneficial insects.
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How to Grow Rudbeckia: Black-eyed Susan Growing Tips
Rudbeckia belongs to the Asteraceae family and is native to North America; however, it can now be found growing worldwide.
Rudbeckia blooms from mid to late summer into fall and grows best in temperatures between 70-85°F (21-29.4°C) during the day and above 55°F (12.7°C) at night. Once established, Rudbeckia plants can tolerate drought conditions and higher temperatures. As a result, rudbeckia often survives and thrives during the intensely hot summers of my low desert Arizona garden.
Rudbeckia is a hardy plant that can also thrive in cooler temperatures. In addition, it can withstand light frost, making rudbeckia a good choice for gardens in cooler climates.
Rudbeckia varieties to try:
Black-eyed Susan varieties can be annual, biennial, or perennial, and they grow well in zones 3-9.
Rudbeckia plants can grow up to 3 feet tall and 2 feet wide. Depending on the variety, the flowers can range from 1-7 inches in diameter.
Rudbeckia hirta varieties to try:
- Cherokee Sunset Mix: Tall cutting variety with large, double, bicolor flowers.
- Cherry Brandy: Red variety available from seed.
- Chim Chiminee Mix: Rust tones with large flower heads and quilled petals.
- Denver Daisy: Large yellow blooms with red centers and unique coloring.
- Indian Summer: Large blooms with yellow petals and black centers.
- Black-Eyed Susan: Heirloom, native wildflower blooms for 8 weeks or more.
Rudbeckia triloba: Tall 5-6’ (1.6-2m) with multiple stems on each plant.
Rudbeckia hirta and Rudbeckia triloba varieties are best suited for cutting.
When to plant rudbeckia:
Plant seeds or transplants outside once the soil warms to 70°F (21°C). Fall planting results in earlier spring blooms.
When to plant rudbeckia in the low desert of Arizona:
Choose the right location to plant black-eyed Susans:
Rudbeckia needs at least 6 hours of sunlight to thrive. It tolerates shade but will not produce as many flowers as in full sun. The soil should be fertile, well-draining, and moist. Rudbeckia grows best in loamy or sandy soil that is slightly acidic to neutral pH.
How to plant rudbeckia:
Start annual or biennial types from seed. Divide perennial cultivars in the spring or fall.
If you want to get a head start on growing rudbeckia:
- Cold moist stratify seeds 3-4 weeks before starting the seeds indoors or outside if planting in warm climates. (not always necessary, but can aid in germination/flowering)
- Start indoors 6-8 weeks before planting outside.
- Plant the seeds in seed starting mix and keep them moist until they germinate.
- Harden off seedlings before planting them outside.
- Plant seedlings once they are 3-5” tall.
To plant rudbeckia seeds in the garden, wait until the soil warms to 70°F (21°C). Then, lightly cover the seeds with soil and keep them moist until they germinate.
Plant rudbeckia transplants at the same level as in the nursery pot. Ensure good seed to soil contact and water well.
How to grow and care for rudbeckia:
Rudbeckia is a low-maintenance flower that is drought-resistant and grows in various soil types. However, it prefers well-draining soil and needs to be watered regularly until it is established. After that, it can tolerate some drought conditions.
Provide support for tall varieties. Remove any faded flowers to encourage blooming and minimize self-seeding. Keep flowers harvested to promote more blooms.
Proper spacing, removing dead plant material, and avoiding moisture on the leaves can help prevent diseases. Diseases to look out for are crown rot, leaf spot, mildew, and rust.
Divide perennial plants every few years to keep plants healthy and avoid crowding. In colder climates, protect the plant from harsh winter weather. Apply a layer of mulch around the base of the plant to protect the roots from freezing.
Rudbeckia plants are hardy but can still face pest issues. Some common pests are aphids, spider mites, slugs and snails, leafhoppers, and thrips. Treatment options include monitoring and allowing natural predators to take care of it, pruning, using a strong water stream, or (in severe cases) insecticidal soap application. Learn more about organic pest control in this blogpost.
Rudbeckia tips for cut flowers:
When harvesting rudbeckia for cut flowers, harvest anytime after the blooms are at least halfway open. Make the first cut at ground level above 3-4 side shoots. Then, remove all foliage below the flower.
Flowers last 8-10 days in a vase with a floral preservative. Adding a few drops of bleach can prevent murky water common with rudbeckia blooms.
End-of-season care for rudbeckia plants:
At the end of the season, cut back perennial rudbeckia plants to about 6 inches from the ground. This will help encourage new growth the following year. Rudbeckia is an ideal plant for a wildflower garden if allowed to reseed.
To save seeds from rudbeckia leave a blossom or two on the plant until the petals die back and it begins to brown. Clip the blossom from the plant and store it in a paper sack until dry. The seeds are located in the center (the black part) of the flower and can easily be removed once they are dry.