How to Grow Smithiantha 'Coral King'

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Smithiantha 'Coral King'

Smithiantha × hybrida 'Coral King'

flower

Smithiantha 'Coral King' is a tropical, rhizomatous houseplant prized for its stunning coral-red flowers with yellow throats and velvety, deeply veined foliage. This hybrid gesneriad produces cascading clusters of tubular blooms that attract hummingbirds and pollinators. It thrives in warm, humid environments and is ideal for hanging baskets or shaded greenhouse cultivation.

When should you plant Smithiantha 'Coral King' in your zone?

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Example Smithiantha 'Coral King' timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Smithiantha 'Coral King'

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. First Smithiantha 'Coral King' blooms

    Around Aug 15

    ≈ 120 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Smithiantha 'Coral King' dates for your own zip code.

Growing Conditions

☀️
Sun: Bright, indirect light; 12-14 hours daily under grow lights indoors; protect from direct afternoon sun
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Water: Keep soil consistently moist but not waterlogged during growing season; reduce watering significantly during dormancy; use room-temperature or slightly warm water; avoid wetting foliage to prevent leaf spots
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Spacing: 12 inches
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Days to maturity: 120-150 days from rhizome to flowering
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Planting depth: Plant rhizomes 1-1.5 inches deep; keep soil surface slightly moist until growth begins

Soil

Type: Light, well-draining, peat-based or orchid bark mix
pH: 6.0-6.5
Amendments:
Peat moss or coconut coir Orchid bark or perlite Charcoal for drainage Compost for organic matter

Growing Zones

Find your zone →

Zones 10b-11; grown as a houseplant in colder climates

10b 11a 11b

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Growth Stages

1

Dormancy/Rhizome

2-3 months (winter)

Rhizomes are resting, appearing as knobby, scaly underground structures with no visible growth

Store rhizomes in cool, dry conditions (50-60°F) for 2-3 months; keep soil barely moist; provide minimal light

2

Sprouting/Emergence

2-3 weeks

Red shoots and fuzzy leaf buds emerge from rhizomes; new leaves are small and tender

Increase warmth to 65-75°F; provide bright, indirect light; begin regular watering; increase humidity to 60-70%

3

Vegetative Growth

6-8 weeks

Distinctive velvety, dark green leaves with silvery veining expand rapidly; plant develops bushy growth habit

Maintain 70-80°F; provide bright indirect light; fertilize every 2 weeks with diluted balanced or high-nitrogen fertilizer; increase humidity with pebble trays or humidifier

4

Flowering

8-12 weeks

Coral-red tubular flowers with yellow throats appear in cascading clusters above the foliage; blooms are long-lasting

Maintain warm conditions (70-80°F); switch to phosphorus-rich fertilizer to encourage blooming; keep humidity at 60-70%; ensure consistent moisture; remove spent flowers for extended blooming

5

Post-Bloom/Senescence

4-6 weeks

Flowering diminishes; foliage may begin to yellow and decline as plant prepares for dormancy

Gradually reduce watering; allow soil to dry somewhat between waterings; lower temperature to 55-65°F to trigger dormancy; reduce fertilizer; stop watering after foliage dies back completely

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Drafty locations near heating vents or AC Dry-air-loving succulents in same container Plants requiring drought conditions

Common Pests

  • Inspect regularly; remove with 70% isopropyl alcohol on cotton swab; spray with insecticidal soap if severe; isolate affected plant

  • Increase humidity to 60%+; mist foliage (avoiding flowers); use neem oil or insecticidal soap; ensure good air circulation

  • Allow soil surface to dry slightly between waterings; use yellow sticky traps; apply sand layer on top of soil; consider repotting if infestation is severe

  • Yellow sticky traps; spray undersides of leaves with insecticidal soap; improve air circulation; isolate from other plants

  • Avoid wetting foliage; improve air circulation with gentle fan; remove affected leaves immediately; reduce humidity if leaf spots appear; apply fungicide if necessary

Uses

🍳

Ornamental flowers

Culinary

The spectacular coral-red flowers are occasionally used as decorative elements in gourmet plating and specialty cuisine for their visual appeal. [source]

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Indoor decoration and air purification

Household

Smithiantha 'Coral King' serves as an attractive potted houseplant for interior spaces, adding tropical flair and contributing to indoor air quality in humid environments. [source]

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Hummingbird attraction

Wildlife

The tubular coral-red flowers are highly attractive to hummingbirds and other nectar-feeding insects, making it an excellent choice for pollinator gardens in warm climates. [source]

🎨

Cut flowers and floral arrangements

Craft

The unique coral tubular blooms can be cut and used in short-lived fresh floral arrangements and specialty bouquets for their striking color and exotic appearance. [source]

💊

Traditional herbal use

Medicinal

Some Smithiantha species have been used in traditional South American herbalism, though 'Coral King' is primarily cultivated as an ornamental rather than medicinal specimen. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Not a harvest plant in the traditional sense; deadhead spent flowers to encourage continued blooming throughout the season; flowers can be cut for short-lived indoor arrangements (2-3 days); allow some flowers to remain for hummingbird attraction if growing outdoors in suitable zones

Fun Facts

  • 🌱 Smithiantha 'Coral King' belongs to the Gesneriaceae family, which also includes African violets and gloxinias; it is native to Central and South American cloud forests
  • 🌱 The name 'Smithiantha' honors one of the plant's early cultivators; this hybrid was developed through selective breeding to enhance flower color intensity and bloom duration
  • 🌱 The velvety texture on Smithiantha leaves comes from thousands of tiny hairs (trichomes) that help the plant absorb moisture and nutrients in its humid native habitat; these hairs also give it a silvery appearance

Gardening Terms

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

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