Rudbeckia Growing Guide: How to Grow Black-Eyed Susan for Colour From July to November
Everything you need to grow rudbeckia successfully — from choosing the right species and sowing from seed to planting, care, and dealing with the few problems that occasionally arise. Covers R. hirta, R. fulgida ‘Goldsturm’, R. laciniata and more, with USDA zone guidance for zones 3–9.
Rudbeckia fills the gap that most gardeners dread: the weeks from late July through October when the border has peaked and started declining. Bold golden flowers with near-black central cones keep blooming reliably after dahlias sulk, before asters fully open, and through conditions that would finish a lesser plant. Native to North American prairies, rudbeckia evolved for exactly the kind of summer heat, drought, and poor soil that challenges most gardens.
This growing guide covers the complete picture: species and variety selection, growing from seed, planting, ongoing care, common problems, and companion planting. For the story behind the name and the flower’s symbolism in American culture, see our rudbeckia flower meaning guide.
What is Rudbeckia?
Rudbeckia is a genus of 23 or more species in the daisy family (Asteraceae), native entirely to North America. The common name Black-Eyed Susan refers to the distinctive dark brown to nearly black central disc — the “eye” — surrounded by bright golden-yellow ray petals. Carl Linnaeus named the genus in 1753 in honor of Olof Rudbeck the Elder and Younger, Swedish botanists and Linnaeus’s academic predecessors.
They look similar but grow very differently — black eyed susan vs coneflower explains.
In their native habitat, rudbeckias grow in open prairies, meadows, roadsides, and the edges of woodlands from southern Canada down through the eastern and central United States. This origin explains their core growing preferences: full sun, seasonal drought, and soils that are often thin and nutrient-poor.
The four species most commonly grown in North American gardens are:
- Rudbeckia hirta — the classic Black-Eyed Susan, grown as an annual or short-lived biennial. It is Maryland’s state flower, adopted in 1918, and the species most widely sold as bedding plants. Heights range from 10 inches (compact cultivars) to 3 feet; it blooms reliably in its first year from seed, making it the fastest rudbeckia for instant color.
- Rudbeckia fulgida — the perennial Black-Eyed Susan, reliably returning year after year in zones 3–9. The cultivar ‘Goldsturm’ is probably the most planted perennial in North America. Height 18–24 inches; spreads steadily by rhizome and self-seeding.
- Rudbeckia laciniata — Cutleaf Coneflower. A tall, dramatic species reaching 4–6 feet with deeply lobed leaves. Native to moist woodland edges and stream banks; more shade-tolerant than other species. Good for the back of large borders.
- Rudbeckia triloba — Brown-Eyed Susan or Three-Lobed Coneflower. A branching biennial or short-lived perennial producing masses of small flowers (1–2 inches across) over an exceptionally long season. Self-seeds prolifically; excellent for naturalistic plantings and wildlife gardens.
Hardy across USDA zones 3–9 (species-dependent), rudbeckia grows successfully from the coldest northern states through the warm South. Heights span from 10-inch compact annuals to 6-foot perennial species, giving gardeners options from front-of-border to structural back planting.
Best Rudbeckia Varieties
The range of rudbeckia cultivars is wide, but a handful stand out consistently for garden performance, reliability, and impact. The table below covers the five best across different garden uses and situations.
| Variety | Type | Height | USDA Zones | Bloom Time | Notes |
|---|---|---|---|---|---|
| R. hirta ‘Indian Summer’ | Annual / Biennial | 2–3 ft | 3–9 | Jul–Oct | Flowers 6–9 in diameter — almost double the species norm. All-America Selections winner. Superb for cutting. |
| R. fulgida var. sullivantii ‘Goldsturm’ | Perennial | 2 ft | 3–9 | Jul–Oct | RHS Award of Garden Merit. Compact, uniform habit, extended bloom. The benchmark perennial rudbeckia. |
| R. hirta ‘Becky’ | Annual | 10 in | 3–9 | Jun–Sep | Dwarf compact habit. Ideal for containers (minimum 12-inch pot) and front-of-border edging. All-America Selections winner. |
| R. laciniata ‘Herbstsonne’ | Perennial | 5–6 ft | 3–9 | Jul–Sep | Bold architectural back-of-border plant. Drooping lemon-yellow petals around a green cone. Requires staking in exposed sites. |
| R. triloba ‘Prairie Glow’ | Biennial | 2–3 ft | 4–9 | Jul–Sep | Small prolific flowers in warm orange-yellow. Self-seeds readily; excellent for naturalistic plantings and wildlife gardens. |
Growing Rudbeckia from Seed
Both annual and perennial rudbeckias can be grown from seed, though the approach differs significantly between species.
R. hirta (Annual / Biennial) from Seed
Start seeds indoors 6–8 weeks before your last expected frost date. Sow onto the surface of moist seed-starting mix and either leave uncovered or cover very lightly with a fine layer of vermiculite — rudbeckia seeds need light to germinate. Maintain soil temperature at 65–70°F (18–21°C); a heat mat beneath the tray is helpful in cool climates.
Germination takes 7–21 days. Once seedlings reach 2–3 inches and have developed their first set of true leaves, pot them on into individual 3-inch containers. Harden off for 7–10 days before transplanting outdoors after the last frost date.
Alternatively, direct sow outdoors after your last frost date. Prepare the seedbed, scatter seeds thinly, and press lightly into the surface. Thin to 18 inches apart once seedlings are established. Direct-sown plants typically bloom slightly later than indoor-started transplants.
R. hirta blooms in its first year from seed when started indoors early enough — this is one of its key advantages over most perennials that take longer to establish.
R. fulgida (Perennial) from Seed
Perennial rudbeckias are slower and less predictable from seed than their annual relatives. Many gardeners find it more reliable to buy established plants or divide existing clumps, but seed propagation is certainly possible.
The most important step is cold stratification: place seeds in a damp paper towel inside a sealed plastic bag and refrigerate at 35–40°F (2–4°C) for 30 days. This mimics winter conditions and significantly improves germination rates. Research on native prairie species confirms that cold stratification can significantly improve germination success in R. fulgida compared to unstratified seeds, often doubling germination rates.
After stratification, sow indoors 10–12 weeks before your last frost date at 65–70°F. Germination is slower (14–28 days) and less uniform than R. hirta. Seedlings may not bloom until their second year, so most gardeners start perennial rudbeckias from seed in late winter for transplanting the following spring.
Planting Rudbeckia
Getting the site conditions right is the foundation of rudbeckia success — this is a plant that rewards good placement with a decade of reliable blooms and minimal attention.
Light
Rudbeckia requires full sun. A minimum of 6 hours of direct sun per day is needed for flowering; 8 hours produces the best results. Plants in partial shade (3–4 hours of sun) will grow but produce noticeably fewer flowers — often 30–40% fewer blooms compared to full sun plants in the same garden. R. laciniata is the most shade-tolerant species and can manage in dappled shade, but even it performs best with good light.
Soil
One of rudbeckia’s most valuable characteristics is its tolerance of difficult soils. It grows successfully in poor, thin, dry, and rocky conditions that would defeat most ornamental perennials. However, it produces its best growth in moderately fertile, well-drained soil with a pH of 6.0–7.0.
Avoid heavy clay soils that remain waterlogged — this is the one soil condition that rudbeckia handles poorly, particularly in winter. If your soil is heavy, incorporate grit or coarse sand at planting, or raise the bed slightly to improve drainage.
Spacing and Planting
Space annual and biennial rudbeckias 18–24 inches apart. Perennial types, which spread over time, should be planted 24 inches apart to allow mature clumps to develop without crowding. Plant at the same depth as the nursery pot, firm in well, and water thoroughly to settle the roots.
For container growing, compact cultivars like ‘Becky’ perform well in 12-inch pots (minimum). Use a good-quality potting mix with 20–30% perlite for drainage. Container plants need more frequent watering than those in the ground.
The best planting time is spring after the last frost date, or early autumn (September in zones 5 and above) for bare-root perennials. Autumn-planted perennials establish well over winter and often bloom more abundantly in their first summer than spring-planted equivalents.
For companion planting ideas — both practical and aesthetic — see our rudbeckia companion plants guide.
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Watering
Newly planted rudbeckias need consistent moisture during their first growing season — aim for 1 inch of water per week from rainfall or supplemental irrigation. Once established (typically after one full growing season in the ground), rudbeckia is genuinely drought tolerant and one of the most resilient summer-blooming perennials for dry periods. Established R. fulgida will survive extended dry spells without irrigation, though flowering may be slightly reduced during severe drought.
Deadheading
Deadheading — removing spent flowers — is one of the most effective ways to extend rudbeckia’s bloom season. Cutting spent flowers back to the next lateral bud or leaf node diverts the plant’s energy from seed production into producing new buds. In trials, regularly deadheaded plants bloomed for 4–6 weeks longer than undisturbed plants.
The technique is simple: follow the stem of a spent flower down to where the next side shoot or leaf branches off, and cut just above that point. For annual rudbeckias, deadheading also prevents unwanted self-seeding.
Stop deadheading in late September. Allow the final flush of flowers to form seed heads: these are a critical winter food source for goldfinches, sparrows, and other seed-eating birds. The dark dried cones also provide structural winter interest that rivals many dedicated ornamental grasses.
Fertilizing
Rudbeckia is a light feeder. In average or poor soils, apply a balanced slow-release granular fertilizer (such as 10-10-10) in early spring as new growth emerges. In already-fertile garden soil, no feeding may be necessary at all. Avoid high-nitrogen fertilizers, which produce lush leafy growth at the expense of flowers.
Dividing
Perennial R. fulgida spreads steadily and should be divided every 3–4 years to keep clumps vigorous and free-flowering. Division is best done in early spring (March–April) as new growth appears. Dig the clump, split it into sections with a sharp spade (each section should have several shoots and a healthy root system), and replant immediately at the original depth. Divided sections establish quickly and often bloom in the same season.
Common Problems
Rudbeckia is genuinely low-maintenance and largely pest-resistant, but a few issues appear with some regularity.
Powdery Mildew
Powdery mildew (Erysiphe cichoracearum) is the most common rudbeckia problem, appearing as a white powdery coating on leaves, particularly in late summer and in humid climates or where plants are crowded. It rarely kills plants but is unsightly.
Prevention is more effective than treatment: plant in full sun with good air circulation, avoid overhead watering, and don’t overcrowd. If mildew appears, remove affected leaves and apply a potassium bicarbonate or neem oil spray. R. fulgida ‘Goldsturm’ has notably better mildew resistance than R. hirta cultivars and is a good choice for humid gardens or the southeastern United States.
Slugs
Slugs target young seedlings and emerging spring growth. Protect transplants with copper tape around pot rims, diatomaceous earth barriers, or iron phosphate slug bait (safe for wildlife). Established plants are rarely seriously damaged.
Sawfly Larvae
Macrophya punctumalbum sawfly larvae occasionally skeletonize rudbeckia foliage. Handpick when numbers are small; a targeted spray of spinosad handles heavier infestations.
Angular Leaf Spot
Angular leaf spot is a bacterial disease (Pseudomonas syringae) causing water-soaked, angular lesions on leaves, often surrounded by a yellow halo. It is most severe in wet seasons and where plants are watered overhead. No effective chemical control exists; focus on cultural prevention — drip irrigation, good spacing, and removing infected foliage promptly.
Root Rot
Root rot, caused by Pythium and related soilborne pathogens, occurs when rudbeckia is planted in poorly drained, waterlogged soil. The best prevention is choosing a well-drained site and incorporating organic matter and grit into heavy clay soils before planting.
Rudbeckia with Other Plants
Rudbeckia’s warm golden tones and late-season timing make it one of the most versatile partners in the late-summer and autumn garden. For a full guide to the best and worst companions, see our rudbeckia companion plants guide.
Prairie-style planting: Pair rudbeckia with ornamental grasses for a naturalistic North American prairie effect. Miscanthus sinensis ‘Gracillimus’ (maiden grass) provides an elegant tall backdrop; Panicum virgatum ‘Shenandoah’ (switchgrass) with its red autumn tints contrasts beautifully with the golden yellow. This combination looks spectacular from July through January, with the grasses and rudbeckia seed heads persisting long into winter.
Wildlife-friendly border: Combine with echinacea (purple coneflower) and salvia for a border that supports pollinators from May through October. The combination of purple, pink, and gold is particularly attractive to bumblebees, monarch butterflies, and painted ladies. Echinacea blooms slightly earlier than rudbeckia, giving a seamless transition through summer.
Cottage garden: Rudbeckia holds its own against bolder late-season flowers. Try golden rudbeckia with deep purple asters, burgundy dahlias, and the warm tones of crocosmia. The yellow-orange palette bridges warm and cool tones elegantly in an informal border.
Winter structure: Leave seed heads and stems standing through winter rather than cutting back in autumn. Paired with ornamental grasses, the dried rudbeckia provides structural interest and food for overwintering birds until spring.
Rudbeckia: Frequently Asked Questions
Is rudbeckia a perennial or annual?
It depends on the species. Rudbeckia hirta is an annual or short-lived biennial — it grows, flowers, sets seed, and dies within 1–2 years. It does not reliably return after winter. Rudbeckia fulgida is a true perennial; established clumps return reliably for many years in zones 3–9 and slowly spread by rhizome and self-seeding. When gardeners say “my rudbeckia comes back every year,” they usually have R. fulgida, or their R. hirta has self-seeded. If you want guaranteed annual return, choose R. fulgida ‘Goldsturm’.
When does rudbeckia bloom?
Most rudbeckias begin blooming in July and continue through September or October. R. hirta ‘Becky’ starts as early as June from an early indoor sow. R. fulgida ‘Goldsturm’ typically peaks in August and September — exactly when most summer flowers are declining. In warm climates (zones 7–9), flowering may extend into November with mild autumns. This late-season reliability is one of rudbeckia’s most valuable garden characteristics.
Does rudbeckia come back every year?
Perennial species (R. fulgida, R. laciniata, R. maxima) come back reliably every year in their hardiness zones. Annual species (R. hirta) do not overwinter but self-seed so prolifically that new plants appear the following spring, creating the impression of a perennial. In practice, a mixed rudbeckia patch often perpetuates itself indefinitely through a combination of returning perennial clumps and self-seeded annuals. To maximize self-seeding, avoid deadheading the final flowers in September and allow some seed heads to mature and drop naturally.
What is the difference between rudbeckia and echinacea?
Both belong to the daisy family (Asteraceae) and are native to North American prairies, which is why they are often planted together. The differences are significant: echinacea flowers are typically pink, purple, or white with strongly reflexed (downward-drooping) ray petals and a particularly raised, spiny central cone. Rudbeckia flowers are almost always yellow or orange with a flatter, less spiny disc. Echinacea is thought of primarily for its medicinal reputation; rudbeckia is valued for ornamental impact. They share the same growing requirements, bloom at similar times, and attract identical pollinators — making them ideal companions in a wildlife-friendly border.
How do you deadhead rudbeckia?
Deadheading rudbeckia is simple. When a flower is spent — petals browning and drooping — follow the stem down to the first lateral shoot or leaf node below the flower head. Cut cleanly just above this point with sharp secateurs or scissors. This stimulates the plant to produce the next bud from that lateral shoot. Avoid cutting the stem all the way to the ground, which removes productive side shoots. Deadhead every 1–2 weeks during the main flowering season (July–September) for maximum bloom extension. Stop in late September to allow seed heads to form for birds and winter structure.
If you are deciding between Echinacea and Rudbeckia for the same border, see Echinacea vs Rudbeckia for a full comparison of root type, lifespan, bloom timing, and soil requirements.
Sources
- Royal Horticultural Society. Rudbeckia — Plant Guide. RHS.org.uk
- Missouri Botanical Garden. Rudbeckia fulgida var. sullivantii ‘Goldsturm’. PlantFinder
- NC State Extension. Rudbeckia — Plant Profile and Growing Guide. plants.ces.ncsu.edu
- USDA Plants Database. Rudbeckia — Native Range and Hardiness Zones. plants.usda.gov
- All-America Selections. AAS Winner Records — Rudbeckia hirta ‘Indian Summer’ and ‘Becky’. all-americaselections.org
