How to Grow Hawaiian Catchfly

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Hawaiian Catchfly

Silene hawaiensis

flower

Silene hawaiensis is a rare endemic flowering plant native to the Hawaiian Islands, particularly found on the volcanic slopes of Maui and Hawaii. This delicate perennial produces small, pink or white flowers and thrives in the unique microclimates of Hawaiian montane forests. It is critically endangered in its native habitat and is primarily cultivated by specialized horticulturists and botanical institutions.

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Example Hawaiian Catchfly timeline · Pittsburgh, PA (Zone 6b)

Plant Hawaiian Catchfly
Around Apr 17

Near Pittsburgh's average last spring frost.
Tend & protect
Late spring–summer

Watering, feeding, and pest-watch reminders.
First Hawaiian Catchfly blooms
Around Jul 16

≈ 90 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Hawaiian Catchfly dates for your own zip code.

Growing Conditions

☀️

Sun: Partial shade to dappled sunlight; 3-5 hours of indirect light daily

💧

Water: Moderate watering; keep soil consistently moist but not waterlogged. Reduce water in winter. Prefer humidity levels similar to Hawaiian forest understory.

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Spacing: 12 inches

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Days to maturity: 90-120 days to first flowering from well-established seedlings

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Planting depth: Surface sow or barely cover seeds; requires light to germinate

Soil

Type: Well-draining, sandy loam with organic matter; mimics volcanic Hawaiian soils

pH: 6.0-7.0

Amendments:

Perlite or pumice for drainage Compost or aged bark Gritty sand to simulate volcanic substrate

Growing Zones

Find your zone →

Thrives in zones 10-11; requires warm, tropical to subtropical conditions

10a 10b 11a 11b

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Growth Stages

Germination

2-4 weeks

Tiny seedlings emerge with cotyledons; very delicate and slow-growing

Maintain high humidity, use misting. Keep under lights. Avoid direct sun and waterlogging. May take 2-4 weeks to emerge.

Seedling

4-8 weeks

First true leaves appear; growth remains slow with typical alpine/endemic characteristics

Provide gentle air circulation to prevent damping off. Keep humidity moderate. Begin careful fertilization with dilute, balanced fertilizer.

Vegetative

6-12 weeks

Plant develops rosette of small leaves; establishes root system gradually

Maintain consistent moisture and partial shade. Ensure excellent drainage. Avoid high nitrogen fertilization which promotes weak growth.

Pre-flowering

2-4 weeks

Small buds begin forming at stem tips; plant strengthens and grows more robust

Reduce watering slightly. Increase light exposure gradually if grown indoors. Ensure nutrients are balanced.

Flowering

4-8 weeks or longer

Small pink or white flowers appear in terminal clusters; delicate and ephemeral blooms

Maintain moderate moisture. Provide consistent partial shade. Deadhead spent flowers to encourage continued blooming. Avoid temperature extremes.

Companion Planting

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Plant with:

Ohi'a Lehua (Metrosideros polymorpha) Hawaiian Native Ferns Ohelo (Vaccinium reticulatum) Naupaka (Scaevola)

Avoid planting near:

Strong herbicides Aggressive invasive species (Banana Poka, Miconia) Aggressive companion plantings that shade or compete heavily

Common Pests

Increase humidity, mist foliage regularly. Use insecticidal soap or neem oil if severe. Avoid excessive heat.
Reduce soil moisture slightly. Use yellow sticky traps. Ensure good air circulation. Apply nematodes or sand top-dressing.
Improve air circulation. Avoid wetting foliage. Apply sulfur spray or baking soda solution if needed.
Inspect regularly and remove by hand. Apply horticultural oil spray on dormant or semi-dormant growth.

Uses

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Conservation & Botanical Collection

Craft

Silene hawaiensis is cultivated primarily by botanical gardens, seed banks, and conservation programs dedicated to saving Hawaiian endemic flora. Growing this species contributes to species preservation and genetic diversity banking. [source]

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Native Pollinator Support

Wildlife

The delicate pink or white flowers provide nectar for Hawaiian native insects and pollinators including endemic arthropods and birds when grown in appropriate settings. [source]

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Ornamental Specialty Plant

Household

Valued by native plant enthusiasts and tropical gardeners for its rare beauty, delicate flowers, and botanical significance as a Hawaiian endemic species. [source]

Harvest Tips

Not typically harvested; grown ornamentally for its rare, delicate flowers. Collect seeds in late summer if available; dry thoroughly before storage at cool temperatures.

Fun Facts

🌱 Silene hawaiensis is critically endangered, with only a handful of wild populations remaining on the slopes of Maui and Hawaii Island, making cultivated specimens precious to conservation efforts.
🌱 The genus Silene includes over 700 species worldwide, but S. hawaiensis is unique to Hawaii and represents an example of adaptive radiation in isolated island ecosystems.
🌱 Hawaiian native plants like Silene hawaiensis often have slow growth rates as an adaptation to the stable island environment with limited competition and resources.

Gardening Terms

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

Damping Off Deadhead Partial Shade Perennial pH True Leaves

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