How to Grow Red Flash
Wikimedia Commons
Red Flash
Iresine herbstii 'Red Flash'
shrubRed Flash is a tender perennial foliage plant prized for its vibrant deep red to burgundy leaves with contrasting bright red or pink veining. It's a compact, bushy houseplant or seasonal outdoor ornamental that adds dramatic color to gardens, containers, and interior spaces. This cultivar is a tropical plant that thrives in warm conditions and is typically grown as an annual in temperate climates.
When should you plant Red Flash in your zone?
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Example Red Flash timeline · Pittsburgh, PA (Zone 6b)
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Plant Red Flash
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Red Flash
Around May 17≈ 30 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Red Flash dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Zones 10b-11; grow as an annual or houseplant in cooler zones
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Get my Red Flash timeline →Growth Stages
Seedling/Propagation
2-3 weeksSmall plantlets with emerging red-tinted foliage, typically propagated from cuttings rather than seed
Maintain high humidity (70%+) and warm temperatures (70-75°F). Use rooting hormone for cuttings. Keep soil moist but not soggy. Root development takes 2-3 weeks.
Vegetative Growth
4-6 weeksPlant develops bushy form with increasingly vibrant red and veined leaves. Stems elongate and branch prolifically
Pinch back growing tips every 2-3 weeks to encourage bushiness and prevent legginess. Provide consistent warmth (65-75°F), moisture, and bright light. Fertilize every 2 weeks with balanced or nitrogen-rich fertilizer.
Established/Mature Foliage
Ongoing until season end or dormancyFull-sized compact shrub with dense, richly colored deep red foliage and prominent veining; reaches 18-30 inches tall depending on cultivar and conditions
Continue pinching back to maintain shape and density. Water regularly and maintain humidity. Fertilize monthly. Remove any faded or damaged leaves. Monitor for pests in warm conditions.
Overwintering/Dormancy (indoors)
3-4 monthsPlant slows growth significantly; foliage may lose some intensity in lower light. If kept outdoors, plant dies back in frost
Move indoors before first frost in cool climates. Reduce watering frequency. Provide bright light and warmer temperatures (60-65°F minimum). Reduce fertilizing. Cut back in spring to rejuvenate.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Increase humidity by misting; spray with water or insecticidal soap; use neem oil in severe cases
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Remove with cotton swab dipped in rubbing alcohol; spray with insecticidal soap or neem oil
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Use yellow sticky traps; spray with insecticidal soap or neem oil; maintain good air circulation
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Scrape off manually or treat with horticultural oil; apply insecticidal soap for crawlers
Uses
Ornamental Container Gardening
CraftRed Flash excels in mixed container plantings, hanging baskets, and as a specimen houseplant. Its dramatic foliage creates vibrant color contrast with other plants and serves as a striking focal point in gardens and patios. [source]
Indoor Houseplant & Air Quality
HouseholdAs a tropical houseplant, Red Flash thrives indoors in bright, warm locations and adds visual interest to living spaces year-round. Like many foliage plants, it contributes to indoor air purification. [source]
Seasonal Annual Bedding
CraftIn temperate climates, Red Flash is commonly used as a tender annual for summer garden beds and borders, providing months of consistent burgundy-red color without flowering requirements. [source]
Garden Structure & Visual Interest
WildlifeThe dense, compact growth habit provides microhabitat structure for beneficial insects and adds textural depth to landscape designs through foliage variety. [source]
Harvest Tips
Red Flash is grown for foliage, not harvest. Pinch off stem tips regularly (every 2-3 weeks during growing season) to encourage bushiness and maintain ornamental shape. Use pinched stems for propagation via cuttings. Remove dead or discolored leaves as needed.
Fun Facts
- 🌱 Red Flash foliage intensity increases with bright light exposure; plants grown in lower light develop less vibrant coloring and more green tones.
- 🌱 The plant's striking red veining is caused by anthocyanin pigments, the same compounds that give red wine and blueberries their color.
- 🌱 Red Flash is incredibly easy to propagate from stem cuttings—simply place a 3-4 inch cutting in moist soil or water and roots develop within 2-3 weeks.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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