How to Grow Red Knight Alternanthera
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Red Knight Alternanthera
Alternanthera dentata 'Red Knight'
shrubRed Knight Alternanthera is a vibrant ornamental foliage plant prized for its deep burgundy to crimson leaves with metallic red undersides. This compact, bushy cultivar is commonly used in tropical and subtropical gardens, containers, and as a colorful annual bedding plant in temperate regions. It produces inconspicuous white or cream-colored flowers, but the striking foliage is the main attraction.
When should you plant Red Knight Alternanthera in your zone?
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Example Red Knight Alternanthera timeline · Pittsburgh, PA (Zone 6b)
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Plant Red Knight Alternanthera
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 Knight Alternanthera
Around May 17≈ 30 days after planting
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Growing Conditions
Soil
Growing Zones
Find your zone →Zones 9b-12; grown as an annual in cooler zones or overwintered indoors
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Seedling & Transplant
3-4 weeksSmall plants with minimal foliage; leaves may be green or showing early red coloration
Maintain warm soil (70-80°F), keep moist but not soggy, provide bright indirect light. Harden off transplants before moving outdoors.
Vegetative Growth
4-6 weeksBushy plant with increasing leaf development; foliage intensifies from red to deep burgundy with metallic sheen
Increase sunlight exposure to develop full color. Pinch growing tips to encourage bushier growth. Fertilize every 2-3 weeks with balanced fertilizer.
Flowering
Intermittent, spring through fallSmall, inconspicuous white or pale cream-colored flowers appear amid the foliage; not the main ornamental feature
Deadheading is optional as flowers are minor. Continue regular watering and fertilizing. Some gardeners remove flowers to focus energy on foliage.
Decline & Overwintering
Fall through early springGrowth slows in cool seasons; foliage may lose vibrancy in low light or frost-prone areas
In zones 9b-10, provide frost protection or move containers indoors. In warm climates (11-12), continue care year-round. Prune back in spring to rejuvenate.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with insecticidal soap or neem oil; inspect regularly and remove affected foliage
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Increase humidity, spray with water mist, or apply miticide if severe
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Use yellow sticky traps, spray with neem oil or insecticidal soap
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Improve drainage, avoid overhead watering, remove affected stems, apply fungicide if needed
Uses
Colorful Bedding & Container Display
OrnamentalRed Knight serves as a stunning accent in garden beds, borders, and containers, providing year-round foliage interest in tropical zones or seasonal color in temperate regions. Its deep burgundy foliage complements other ornamental plants and creates striking color contrasts. [source]
Indoor Houseplant
HouseholdThis cultivar thrives as an indoor potted plant in bright locations, making it ideal for patios, conservatories, or winter protection in cooler climates. It adds tropical flair to interior spaces and is relatively low-maintenance. [source]
Pollinator Support
WildlifeThough flowers are inconspicuous, they provide nectar for small insects and butterflies. The dense foliage also offers shelter for beneficial insects and small pollinators. [source]
Fresh Cut Foliage Arrangements
CraftThe striking burgundy leaves with metallic sheens make excellent material for fresh flower arrangements and floral designs. Cut stems remain vibrant for several days in water. [source]
Edible Ornamental (Regional Use)
CulinaryIn some tropical regions, Alternanthera species are consumed as leafy vegetables with mild, slightly earthy flavors. However, 'Red Knight' is primarily ornamental; verify variety safety before consumption. [source]
Harvest Tips
Red Knight Alternanthera is grown primarily for foliage display rather than harvest. Pinch or prune stems throughout the growing season to encourage bushier growth and maintain shape. Cuttings can be propagated in water or moist soil for new plants. Cut stems just above leaf nodes for best regeneration.
Fun Facts
- 🌱 Red Knight Alternanthera is native to South America and is also known as 'Brazilian Red Hots' or 'Bloodleaf,' reflecting its striking deep red coloration.
- 🌱 The plant's name 'dentata' refers to the finely toothed leaf margins, visible upon close inspection of the burgundy foliage.
- 🌱 Red Knight is often used in aquascaping and paludarium designs due to its ability to tolerate high humidity and semi-aquatic conditions, though it performs best with good air circulation.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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