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Plant care

Rudbeckia 'Autumn Colors' (Autumn Colors black-eyed Susan) care

Rudbeckia hirta 'Autumn Colors'

Also called Autumn Colors black-eyed Susan, Bicolour coneflower.

RHS H6USDA 3-9Mildly toxic to petsIndoor 60-75 cm tall

Watering rhythm

7-10days

When the top 3-4 cm of soil is dry, roughly every 7-10 days

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Light

Direct sun (at least 4-6 hours)

Soil

Well-drained garden loam or sandy soil

Humidity

30-60%

Temp

10-30°C

Pet safety

Mildly toxic to pets

Mature size

60-75 cm tall

Care at a glance

Light

Aim for at least 4-6 hours of direct sun on the leaves. Full sun (6-8+ hours) produces the richest colour range and strongest stems. Insufficient light leads to muted tones and floppy growth. If your only bright window faces south, that's perfect for rudbeckia 'autumn colors' — same window any aroid would fry on.

Watering

Watering rudbeckia 'autumn colors': when the top 3-4 cm of soil is dry, roughly every 7-10 days. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Drought-tolerant once established. Water at the base to keep foliage dry. In prolonged dry spells, a deep soak once a week prevents early leaf drop.

Soil and pot

Rudbeckia 'Autumn Colors' grows best in well-drained garden loam or sandy soil. Tolerates poor soils well. Avoid heavy, waterlogged ground. A neutral pH of 6.0-7.0 suits this cultivar. Add grit to clay soils if needed. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Rudbeckia 'Autumn Colors' sits happiest at around 30-60% humidity and 10-30°C (50-86°F). Not humidity-sensitive. Good spacing and airflow prevent fungal leaf diseases in wetter climates. If you keep the room above 10 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed rudbeckia 'autumn colors' sparingly. Apply a balanced slow-release fertiliser at planting. Supplementary feeding is rarely needed. High nitrogen promotes foliage at the expense of flowers. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on rudbeckia 'autumn colors' in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Powdery mildew — Common in late summer. Space plants well and water at the base.
  • Aphids — Check growing tips regularly; use insecticidal soap at first sign.
  • Botrytis (grey mould) — Can develop in wet, cold conditions. Remove dead plant material and improve airflow.
  • Slugs — Target seedlings. Protect with grit mulch or beer traps.
  • Floppy stems — Occurs in rich soil or shade. Move to full sun and avoid excess fertiliser.

Companion plants

Rudbeckia 'Autumn Colors' pairs well with Miscanthus sinensis, Aster novi-belgii, and Helenium autumnale. These are species with similar light and water needs, so you can group them in the same room or on the same shelf and water as a batch.

Propagation

Start seeds indoors 6-8 weeks before last frost. Sow on the surface (seeds need light to germinate) at 18-21°C. Transplant after the last frost, spacing 30-40 cm apart. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Rudbeckia 'Autumn Colors' is mildly toxic to pets. Rudbeckia hirta is not individually listed on the ASPCA toxic plants database. As with other Rudbeckia, mild gastrointestinal irritation is possible if eaten by pets in quantity. Exercise caution around dogs and cats. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Rudbeckia 'Autumn Colors' care — frequently asked questions

What is the common name for Rudbeckia hirta 'Autumn Colors'?

Rudbeckia hirta 'Autumn Colors' is most commonly called Rudbeckia 'Autumn Colors', but it is also known as Autumn Colors black-eyed Susan, Bicolour coneflower. The names refer to the same species, so care instructions for Rudbeckia 'Autumn Colors' apply identically to anything sold as Autumn Colors black-eyed Susan.

How much light does rudbeckia 'autumn colors' need?

Rudbeckia 'Autumn Colors' grows best in direct sun (at least 4-6 hours). Full sun (6-8+ hours) produces the richest colour range and strongest stems. Insufficient light leads to muted tones and floppy growth.

How often should I water rudbeckia 'autumn colors'?

Water rudbeckia 'autumn colors' when the top 3-4 cm of soil is dry, roughly every 7-10 days. Drought-tolerant once established. Water at the base to keep foliage dry. In prolonged dry spells, a deep soak once a week prevents early leaf drop. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is rudbeckia 'autumn colors' toxic to cats and dogs?

Rudbeckia 'Autumn Colors' is mildly toxic to pets. Rudbeckia hirta is not individually listed on the ASPCA toxic plants database. As with other Rudbeckia, mild gastrointestinal irritation is possible if eaten by pets in quantity. Exercise caution around dogs and cats.

What USDA hardiness zone does rudbeckia 'autumn colors' grow in?

Rudbeckia 'Autumn Colors' is rated for USDA zone 3-9 (commonly grown as an annual) and RHS hardiness H6. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Rudbeckia 'Autumn Colors' deep-dive guides

Every aspect of rudbeckia 'autumn colors' care, each with its own calibrated guide:

Featured in these plant shortlists

Rudbeckia 'Autumn Colors' qualifies for 4 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

Related guides

Rudbeckia 'Autumn Colors' is also commonly called Autumn Colors black-eyed Susan or Bicolour coneflower.