How to Grow Silvery Spike

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Silvery Spike

Acalypha pendula × Iresine herbstii

shrub

Silvery Spike is a striking ornamental foliage plant prized for its silvery-white variegated leaves with deep red or burgundy undersides. It's a tender perennial that thrives as a houseplant or in warm outdoor gardens, adding dramatic color contrast to mixed containers and beds.

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Example Silvery Spike timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Silvery Spike

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Silvery Spike

    Around May 17

    ≈ 30 days after planting

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

Growing Conditions

☀️
Sun: Bright, indirect light preferred; tolerates part shade but colors best in light with 4-6 hours indirect sun daily
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Water: Keep soil consistently moist but not waterlogged during growing season; reduce watering in winter; prefers slightly humid environment
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Spacing: 12 inches
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Days to maturity: 30-45 days to usable size
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Planting depth: Surface sow cuttings or plant rooted transplants at same depth as container

Soil

Type: Well-draining, fertile potting soil or loamy mix
pH: 6.0-6.8
Amendments:
Peat moss or coco coir Perlite or coarse sand Compost or aged bark

Growing Zones

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Zones 10b-11; grow as an annual or container plant in cooler zones

10b 11a 11b

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Growth Stages

1

Propagation/Rooting

10-14 days

Stem cuttings develop roots in water or propagation medium; new growth appears pale

Use 3-4 inch tip cuttings; maintain 70-75°F; mist daily; provide bright indirect light

2

Establishment

2-3 weeks

Young plant develops 2-3 sets of true leaves with emerging variegation and color

Pot into individual containers; maintain warm temperatures; begin light fertilizing; ensure good drainage

3

Vegetative Growth

4-8 weeks

Plant grows rapidly, developing fuller foliage with increasingly prominent silvery-white and burgundy coloring

Pinch tips regularly to encourage branching; fertilize every 2 weeks with balanced fertilizer; maintain moisture

4

Mature Foliage Plant

Ongoing (6+ months)

Plant reaches desired size with full silvery variegation, compact branching, and vibrant leaf color

Maintain shape through pinching; reduce fertilizing in winter; monitor for spider mites; continue consistent watering

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Black walnut (produces juglone toxin) Allelopathic herbs like fennel

Common Pests

  • Increase humidity; spray leaves with water; use insecticidal soap or neem oil weekly if infested

  • Remove with rubbing alcohol on cotton swab; spray with neem oil; isolate affected plant

  • Prune affected stems; spray with horticultural oil or insecticidal soap every 7-10 days

  • Use yellow sticky traps; spray with insecticidal soap or neem oil; improve air circulation

Uses

🏠

Interior Ornamental Display

Household

Silvery Spike serves as a stunning houseplant for bright windowsills, conservatories, and vivariums. Its dramatic silvery-white foliage with burgundy reverses adds sophisticated color contrast to any indoor space. [source]

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Container and Combo Plantings

Craft

Highly valued in mixed container gardens and annual beds for its striking color; works as a thriller, filler, or spiller depending on cultivar form. Provides year-round foliage interest in frost-free regions. [source]

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Tropical Garden Accent

Wildlife

In warm climates, Silvery Spike creates privacy screens, hedges, and tropical garden backgrounds while attracting minimal pest damage in balanced ecosystems. Provides visual structure and height. [source]

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Air-Purifying Foliage Plant

Household

Like many houseplants, Silvery Spike contributes to indoor air quality through photosynthesis and transpiration, improving humidity and oxygen levels in indoor environments. [source]

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Floral Arrangement Greenery

Craft

Delicate stems and variegated leaves work beautifully as supplementary greenery in fresh or dried floral arrangements, adding texture and silvery tones to bouquets. [source]

Harvest Tips

This is a foliage plant, not harvested traditionally. Pinch growing tips every 2-3 weeks to encourage bushier growth and better leaf color development. Propagate from 3-4 inch stem cuttings year-round.

Fun Facts

  • 🌱 Silvery Spike exhibits extraordinary leaf variegation that intensifies under bright light conditions—moving it to brighter locations will enhance the silvery-white coloring and burgundy undersides.
  • 🌱 The plant is frost-tender and will die back if exposed to temperatures below 50°F; it's best treated as a tender annual in cold climates or brought indoors before the first frost.
  • 🌱 Despite being a foliage plant, Silvery Spike occasionally produces small, inconspicuous flowers; however, the foliage is the main ornamental attraction and far outshines any blooms.

Gardening Terms

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

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