How to Grow Autumn Colors

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Autumn Colors

Ricinus communis 'Autumn Colors'

shrub

Autumn Colors is a striking ornamental castor bean plant known for its dramatic foliage that transitions through vibrant shades of burgundy, bronze, and deep purple throughout the growing season. This tender perennial is grown as an annual in most climates and reaches 6-10 feet tall, making it an excellent focal point or backdrop in gardens. The large, deeply lobed leaves and ornamental seed pods add tropical flair to temperate gardens.

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Example Autumn Colors timeline · Pittsburgh, PA (Zone 6b)

Plant Autumn Colors
Around Apr 17

Near Pittsburgh's average last spring frost.
Tend & protect
Late spring–summer

Watering, feeding, and pest-watch reminders.
Harvest Autumn Colors
Around Jul 16

≈ 90 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Autumn Colors dates for your own zip code.

Growing Conditions

☀️

Sun: Full sun, 6-8 hours daily for best color development

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Water: Water regularly but allow soil to dry slightly between waterings. Drought-tolerant once established, but performs better with consistent moisture.

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Spacing: 36 inches

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Days to maturity: 90-120 days

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Planting depth: 1

Soil

Type: Well-draining loamy to sandy soil

pH: 6.0-7.5

Amendments:

Compost Aged manure Perlite for drainage

Growing Zones

Find your zone →

Thrives in zones 9-11; grown as annual in cooler zones

9b 10a 10b 11

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Growth Stages

Seedling

2-3 weeks

Small plants with 2-3 true leaves emerge; foliage shows early purple tinges

Keep soil consistently moist but not waterlogged. Provide bright light and warmth (70-75°F). Thin seedlings to proper spacing once 2-3 inches tall.

Vegetative Growth

6-8 weeks

Rapid expansion of deeply lobed leaves; foliage becomes increasingly dark purple and bronze

Provide full sun for optimal coloration. Water regularly and apply balanced fertilizer every 3-4 weeks. Stake if in windy locations.

Mid-Season Development

4-6 weeks

Plant reaches 3-6 feet tall; foliage displays peak autumn colors with burgundy, bronze, and deep purple hues

Continue regular watering and feeding. Prune lower leaves if desired for a tree-like form. Watch for pests.

Flowering & Pod Formation

6-8 weeks

Spiky flower clusters appear at branch tips, followed by ornamental warty seed pods in red or purple

Reduce nitrogen fertilizer to encourage pod production. Maintain consistent moisture. Handle seed pods carefully as they contain toxic seeds.

Mature/Decline

Until frost or season end

Plant reaches maximum height (6-10 feet); foliage may show stress in late season; seed pods become prominent

In frost-prone areas, prepare for end-of-season frost damage. Collect seed pods before frost if desired. In zones 9-11, may persist through mild winters.

Companion Planting

Plan your garden →

Plant with:

Zinnias Celosia Coleus Begonias Salvia Lantana Ornamental grasses

Avoid planting near:

Vegetables in edible gardens (seeds are toxic) Areas frequented by children or pets

Common Pests

Spray with water to dislodge; use insecticidal soap or neem oil if severe. Increase humidity.
Use yellow sticky traps; apply neem oil or insecticidal soap weekly as needed.
Remove with rubbing alcohol on cotton swab; spray with neem oil or insecticidal soap.
Hand-pick in early morning; use pheromone traps or neem oil spray.

Uses

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Tropical Garden Focal Point

Ornamental

The striking burgundy and bronze foliage makes Autumn Colors an exceptional specimen plant for creating tropical or exotic garden designs in temperate climates. Its substantial height and bold leaf color add dramatic impact to borders and containers. [source]

🍳

Seeds for Castor Oil (Educational Only)

Culinary

Historically, castor bean seeds have been used to produce castor oil, which has medicinal and industrial applications. However, seeds contain ricin, a highly toxic protein, and should NEVER be consumed or processed without expert knowledge. [source]

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Dried Pod Arrangements

Household

The ornamental spiky seed pods dry beautifully and can be used in dried flower arrangements, wreaths, and crafts for autumn-themed decorations. [source]

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Pollinator Attraction

Wildlife

The flowers attract bees and other pollinators to the garden, making this plant valuable for supporting local pollinator populations. [source]

Harvest Tips

Allow seed pods to dry on the plant before collecting. Wear gloves when handling pods as seeds contain toxic ricin. Collect pods when they turn brown and begin to split naturally. Store dried seeds in a cool, dry place. Do not ingest seeds under any circumstances.

Fun Facts

🌱 Autumn Colors can grow 6-10 feet tall in a single season, making it one of the fastest-growing ornamental plants; in tropical zones, it can become a small tree reaching 40 feet.
🌱 The plant is called 'castor bean' because the spotted seeds resemble castor ticks; Ricinus communis gets its scientific name from the Latin word for 'tick.'
🌱 All parts of the plant contain ricin, a highly toxic protein, making seed handling critical—never allow children or pets to touch seed pods, and always wear gloves.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Annual Full Sun Perennial True Leaves

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