How to Grow Hawaiian Nasturtium
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Hawaiian Nasturtium
Nasturtium sandwicense
flowerNasturtium sandwicense is a rare, endemic Hawaiian flowering plant with distinctive trumpet-shaped yellow flowers and attractive round leaves. This delicate plant thrives in the cool, moist conditions of Hawaiian mountain forests and is considered vulnerable in its native habitat. It is prized by specialist gardeners and conservationists for its unique beauty and cultural significance to Hawaii.
When should you plant Hawaiian Nasturtium in your zone?
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Example Hawaiian Nasturtium timeline · Pittsburgh, PA (Zone 6b)
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Plant Hawaiian Nasturtium
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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First Hawaiian Nasturtium blooms
Around Jul 16≈ 90 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Hawaiian Nasturtium dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Best suited to zones 10-11; requires frost-free climates and high humidity
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Get my Hawaiian Nasturtium timeline →Growth Stages
Germination
2-3 weeksSeeds begin sprouting within 10-14 days under warm, humid conditions with consistent moisture
Maintain soil moisture; provide bright indirect light; keep temperature between 65-75°F; use a humidity dome if available
Seedling
3-4 weeksTiny plants develop first true leaves and establish a small root system
Maintain high humidity and consistent moisture; provide bright indirect light; avoid fertilizer until second true leaves appear
Vegetative Growth
4-6 weeksPlant develops multiple leaves and sturdy stems; foliage becomes more robust and lush
Continue high humidity and moist conditions; apply weak diluted fertilizer every 2-3 weeks; prune gently to encourage branching; ensure good air circulation
Flowering
8-12 weeks or longerDistinctive bright yellow trumpet-shaped flowers appear along stems; flowers are fragrant and attract pollinators
Maintain consistent moisture and humidity; continue light fertilizing every 2-3 weeks; remove spent flowers to encourage continued blooming; provide stable temperatures
Seed Development
4-6 weeksAfter pollination, seed pods develop on the plant; seeds mature within pods over several weeks
Allow some flowers to remain for seed collection if desired; keep plant healthy with consistent care; seeds are mature when pods turn brown and dry
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with insecticidal soap or neem oil; rinse foliage with water; introduce ladybugs
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Remove with cotton swabs dipped in rubbing alcohol; spray with neem oil; ensure good air circulation
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Increase humidity to discourage them; spray with water; apply miticide if severe; maintain 60%+ humidity
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Reduce watering frequency slightly; allow soil surface to dry slightly between waterings; use sticky traps
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Improve air circulation; reduce humidity slightly during wet seasons; apply sulfur spray or baking soda solution; remove affected leaves
Uses
Edible Flowers & Garnish
CulinaryNasturtium flowers are edible with a peppery, slightly spicy flavor and can be used fresh as garnish in salads, desserts, and tropical beverages. The flowers add visual interest and a unique taste to gourmet dishes. [source]
Traditional Hawaiian Medicine
MedicinalIn Hawaiian traditional medicine, nasturtiums have been used for their potential anti-inflammatory and antiseptic properties. The plant holds cultural significance in native Hawaiian ethnobotany. [source]
Pollinator Attraction
WildlifeThe bright yellow flowers attract bees, butterflies, and hummingbirds, making it valuable for supporting native Hawaiian pollinators and creating biodiverse garden habitats. [source]
Ornamental & Horticultural Interest
CraftPrized by specialty gardeners and plant collectors for its rarity and unique beauty, Nasturtium sandwicense is featured in conservation gardens and native plant collections throughout Hawaii and specialized nurseries worldwide. [source]
Tropical Container & Terrarium Plant
HouseholdIts compact size and preference for humid, partially shaded conditions make it ideal for growing in terrariums, orchid cases, or container gardens on patios and under shade structures in tropical regions. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
For seed collection, allow flowers to fade on the plant and let seed pods mature until they turn brown and papery (4-6 weeks after flowering). Harvest pods when completely dry, store seeds in a cool, dry place. For ornamental enjoyment, harvest flowers in early morning when fresh; they have a mild fragrance and can be floated in water bowls or used in tropical arrangements.
Fun Facts
- 🌱 Nasturtium sandwicense is endemic to Hawaii and is found only on the islands of Maui and Hawaii (Big Island) in native cloud forests at elevations between 4,000-8,000 feet, making it one of Hawaii's rarest flowering plants.
- 🌱 The genus name 'Nasturtium' comes from the Latin words 'nasus' (nose) and 'tortus' (twisted), referring to the peppery scent and pungent flavor that causes a reaction in the nose when tasted.
- 🌱 This species is considered vulnerable to extinction in the wild due to habitat loss, invasive species, and climate change, making cultivation in gardens an important part of conservation efforts for this Hawaiian endemic.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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