How to Grow Red Margin
Wikimedia Commons
Red Margin
Alternanthera dentata 'Red Margin'
shrubRed Margin is a tropical foliage plant prized for its striking deep green leaves with vibrant red to burgundy margins and veins. It grows as a compact, bushy shrub and is commonly used as an ornamental houseplant or outdoor accent plant in warm climates. The colorful foliage provides year-round visual interest with minimal flowers.
When should you plant Red Margin in your zone?
Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.
Example Red Margin timeline · Pittsburgh, PA (Zone 6b)
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Plant Red Margin
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 Margin
Around May 17≈ 30 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Red Margin dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 10b-11; grown as an annual or houseplant in cooler zones
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Get my Red Margin timeline →Growth Stages
Seedling/Propagation
2-3 weeksSmall plants with basic green foliage emerging; minimal red coloring visible initially
Keep soil warm (70-75°F), maintain high humidity, provide bright indirect light, water gently to avoid damping off
Vegetative Growth
3-6 weeksFoliage expands rapidly; red margins become more prominent; plant develops bushy shape with multiple leaf nodes
Increase light exposure to enhance red coloring, pinch back growing tips to encourage branching, maintain consistent moisture and humidity
Established Growth
Ongoing (several months to years)Plant reaches mature size with fully colored leaves showing deep red margins; dense, compact form; may occasionally produce small white or purple flowers
Continue pinching and pruning to maintain shape, feed with balanced fertilizer every 2-4 weeks during growing season, ensure adequate light for color intensity
Maintenance/Pruning
SeasonalMature plant may become leggy or overgrown if not managed; foliage color remains vibrant with proper care
Prune back leggy stems by one-third to one-half in spring, remove any all-green or faded growth, rejuvenate older plants with hard pruning
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Increase humidity, spray with water to dislodge, use neem oil or insecticidal soap if infestation is severe
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Remove with cotton swab dipped in rubbing alcohol, spray with neem oil, improve air circulation
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Scrape off with fingernail or soft brush, treat with horticultural oil or neem oil spray
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Use yellow sticky traps, spray with insecticidal soap, increase air circulation, encourage beneficial insects
Uses
Indoor Ornamental Décor
HouseholdRed Margin is a stunning container plant for indoor spaces, adding tropical color and visual interest to homes, offices, and conservatories. Its compact growth habit makes it ideal for shelves, desks, and windowsills. [source]
Outdoor Landscaping Accent
HouseholdIn warm climates, Red Margin serves as a colorful accent plant in garden borders, mixed containers, and tropical landscape designs. It brightens shaded garden corners and complements other foliage plants. [source]
Floral Arrangements & Crafts
CraftThe striking red-margined foliage is valuable in fresh flower arrangements, dried arrangements, and crafting projects. Leaves can be pressed or preserved for botanical art. [source]
Pollinator Garden Support
WildlifeAlthough grown primarily for foliage, Red Margin's occasional white or purple flowers attract small pollinators and insects, supporting garden biodiversity. [source]
Harvest Tips
Not typically harvested for fruit or seeds as it is grown for ornamental foliage. Cuttings can be taken year-round for propagation; best results occur in spring and early summer. Take 3-4 inch cuttings from new growth, remove lower leaves, and root in moist potting mix or water.
Fun Facts
- 🌱 Red Margin is a cultivar of Alternanthera dentata, a tropical plant native to South America, and is also called Joseph's Coat or Scarlet Pimpernel in some regions.
- 🌱 The intensity of the red coloring increases with more sunlight exposure; plants grown in lower light will have more muted red tones, while bright light intensifies the burgundy margins dramatically.
- 🌱 Red Margin is commonly used in aquascaping (planted aquariums) as a stem plant, where it displays brilliant coloration when grown emersed (partially above water).
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