Rudbeckia hirta, commonly known as Black-eyed Susan, is a beautiful and versatile flowering plant that is highly favored by gardeners. It belongs to the Asteraceae family and is native to North America.
This herbaceous perennial is known for its striking golden-yellow petals surrounding a dark brown or black center, creating a distinctive "black eye" appearance.
Black-eyed Susans typically reach a height of 2 to 3 feet (60 to 90 cm) and spread about 1 to 2 feet (30 to 60 cm).
Gardeners are drawn to Rudbeckia plants for several reasons:
Firstly, its vibrant blooms add a burst of color to any garden, attracting bees, butterflies, and other pollinators. Secondly, it is a hardy plant that requires minimal maintenance once established.
Plants have a long blooming period, usually from mid-summer to fall, providing continuous visual interest in the garden.
This versatile plant is suitable for various garden types, including flower beds, borders, cottage gardens, meadows, and even containers.
Its naturalized and wildflower-like appearance makes it a great choice for informal or naturalistic garden designs. Rudbeckia hirta is also drought-tolerant, making it ideal for water-wise and xeriscape gardens.
In terms of growing zones, Rudbeckia hirta thrives in USDA zones 3 to 9. It is adaptable to different soil types, but it prefers well-draining soil with a pH range of 5.5 to 7.5.
The plant performs best in full sun, although it can tolerate partial shade. While it can withstand dry conditions, regular watering during periods of prolonged drought will help maintain optimal growth and blooming.
When it comes to potential invasiveness, Rudbeckia hirta is generally well-behaved and not considered invasive in most regions. However, it does have the ability to self-seed, so gardeners who want to control its spread should deadhead spent flowers before they develop seed heads. This prevents the plant from dispersing its seeds and spreading to unwanted areas.
How to grow Rudbeckia hirta in the garden:
To successfully grow Rudbeckia hirta in your garden, follow these guidelines:
Location: Choose a sunny spot in your garden with well-draining soil. Ensure that the location receives at least 6 hours of direct sunlight each day.
Soil type: Rudbeckia hirta is adaptable to different soil types but prefers well-draining soil. Improve heavy clay soil by adding organic matter such as compost or well-rotted manure.
Sowing/planting times: The best time to sow black-eyed Susan seeds is in early spring after the danger of frost has passed. You can also start seeds indoors 6 to 8 weeks before the last frost date and transplant them outdoors once the soil has warmed up. Established plants can be divided and transplanted in early spring or early fall.
Planting method: Sow the seeds directly into the prepared soil or place transplants at a spacing of 12 to 18 inches (30 to 45 cm) apart. Plant them at the same depth they were growing in their containers.
Watering: While Rudbeckia hirta is drought-tolerant, water the plants regularly during dry periods, especially in the first few weeks after planting or sowing. Provide deep, thorough watering to encourage strong root development.
Maintenance: Deadhead spent flowers regularly to prevent self-seeding and encourage prolonged blooming. In late fall, cut back the plants to ground level and apply a layer of mulch to protect the roots during winter.
By following these simple guidelines, you can enjoy the beauty of Rudbeckia hirta in your garden and create a vibrant and pollinator-friendly space.
Quick Growing and Care Guide
Scientific Name: Rudbeckia hirta
Common Names: Black-eyed Susan, Gloriosa Daisy
Growing Zone (USA / UK Hardiness): USDA Zones: 3-9, RHS Hardiness Rating: H6
Best Used For / Garden Location: Rudbeckia hirta is best used for borders, wildflower meadows, and cottage gardens. It thrives in full sun and well-drained soil.
Plant Details
Life Cycle / Plant Type: Perennial
Plant Height: 12-36 inches (30-90 cm)
Plant Spread: 12-18 inches (30-45 cm)
Blooms: Summer to fall.
Flower Details: Large daisy-like flowers with yellow or orange petals and dark centers.
Leaf Foliage: Green leaves, lance-shaped with rough texture.
Fruit: Small, inconspicuous seeds.
Growing Conditions and Location
Best Light Conditions: Full sun to light shade.
Suitable Soil Types: Well-drained soil, average fertility.
Sowing / planting: Sow seeds in early spring or fall, or plant established seedlings in spring. Space plants 12-18 inches apart.
Germination time: Germination typically takes 7-21 days at temperatures around 70°F (21°C).
Propagation: Seeds can be sown directly in the garden or started indoors 6-8 weeks before the last frost date.
Plant Care: Water regularly, especially during dry periods. Deadhead spent flowers to prolong blooming. Cut back in late fall or early spring.
Growing in pots and containers: Rudbeckia hirta can be grown in containers. Use a well-draining potting mix and provide full sun. Water regularly and fertilize during the growing season.
Growing as a House plant: Rudbeckia hirta is primarily grown as an outdoor plant and is not commonly cultivated as a houseplant.
Further Information
Miscellaneous: Tolerant to deer and rabbits. Attracts bees, butterflies, and birds.
Rudbeckia hirta can be invasive in some regions, particularly in areas where it is not native. It may self-seed prolifically and spread beyond its intended area. It is important to check with local authorities or gardening experts to ensure it is not invasive in your specific area before planting it.
Pests and diseases: Generally pest and disease resistant. Occasional issues with aphids, powdery mildew, or leaf spot.
Common Cultivars / Varieties: 'Indian Summer', 'Toto', 'Cherry Brandy', 'Prairie Sun'
Family: Asteraceae (The Aster family)
Native: Native to North America.
References and Further Reading: Missouri Botanical Garden, Royal Horticultural Society, University of Minnesota Extension
Common Questions
Is Rudbeckia hirta a perennial?
Yes, Black-eyed Susan, is a perennial plant. This means that once planted, it will come back year after year and continue to bloom.
How long and at what temperature does Rudbeckia hirta germination occur?
Rudbeckia hirta, or black-eyed Susan, typically germinates within 10 to 20 days. The ideal temperature range for germination is around 70 to 75°F (21 to 24°C). Providing a consistent temperature within this range will help promote successful germination of Rudbeckia hirta seeds.
Can Black eyed Susan be easily grown from seed?
Yes, they can be easily grown from seed. The seeds are relatively easy to handle and germinate well when provided with the right conditions. Sow the seeds directly into the garden soil or start them indoors and transplant them later.
When do they Bloom?
Black-eyed Susan (Rudbeckia hirta) typically blooms from mid-summer to fall. The exact timing of blooming can vary depending on the growing conditions and the specific cultivar or variety being grown.
Summary
Rudbeckia hirta, also known as black-eyed Susan, is a vibrant flowering plant favored by gardeners. It features golden-yellow petals surrounding a dark center. Grow it in a sunny spot with well-draining soil, sow seeds in early spring or transplant established plants, and provide regular watering and maintenance.
I hope that you enjoyed this guide on how to grow Rudbeckia Hirta. You may also enjoy the following growing guides: How to grow Mexican Aster, Gazania, and Carthamus plants.
