Lava Dock: Hawaii’s Unique Native Shrub for Specialized Gardens
Meet lava dock (Rumex skottsbergii), one of Hawaii’s most specialized native plants. This unique perennial shrub has adapted to thrive in some of the most challenging volcanic environments, making it a fascinating addition to the right garden setting. But before you start planning where to plant it, there are some important things every gardener should know about this rare Hawaiian endemic.
What Makes Lava Dock Special?
Lava dock is a true Hawaiian original – it’s found nowhere else in the world except the volcanic landscapes of Hawaii. This hardy perennial shrub typically grows as a multi-stemmed woody plant, usually staying under 13-16 feet tall, though it can vary depending on growing conditions.
What sets this plant apart is its incredible adaptation to volcanic soils and harsh, dry conditions. The plant develops reddish stems and narrow leaves that can take on attractive reddish tones when stressed by drought – a natural survival mechanism that also happens to look pretty striking in the garden.
Where Does Lava Dock Grow?
This remarkable plant is endemic to Hawaii, where it grows naturally on volcanic substrates, particularly on the Big Island. Its specialized habitat requirements mean it’s perfectly adapted to the unique conditions found in Hawaiian lava fields and rocky outcrops.
Important Conservation Considerations
Here’s something crucial for responsible gardeners: lava dock has an uncertain conservation status, which suggests it may be quite rare in the wild. This means that while it’s an amazing plant worth growing, you should only source it from reputable native plant nurseries that propagate their stock responsibly rather than collecting from wild populations.
Is Lava Dock Right for Your Garden?
Lava dock isn’t your typical garden plant – it’s best suited for very specific garden styles and conditions:
- Xerophytic (dry) gardens that celebrate drought-tolerant plants
- Rock gardens with excellent drainage
- Native Hawaiian landscape designs
- Specialty collections of unusual plants
This plant thrives in USDA hardiness zones 10-12, so it’s really only suitable for tropical and subtropical climates. If you live outside Hawaii or similar climates, lava dock probably isn’t going to work in your garden.
Growing Conditions and Care
Think volcanic and you’ll understand what lava dock needs:
- Soil: Extremely well-draining, rocky or volcanic soils – regular garden soil will likely be too rich and hold too much moisture
- Sun: Full sun exposure
- Water: Drought-tolerant once established; actually prefers dry conditions and can be damaged by too much water
- Drainage: This cannot be overstated – excellent drainage is absolutely critical
Planting and Care Tips
Successfully growing lava dock is all about mimicking its natural volcanic habitat:
- Plant in a raised bed or slope to ensure perfect drainage
- Amend soil with lava rock, pumice, or coarse sand if needed
- Water sparingly during establishment, then rely on natural rainfall
- Avoid fertilizers – this plant is adapted to nutrient-poor soils
- Protect from areas that collect water or stay moist
Wildlife and Ecological Benefits
While specific wildlife benefits aren’t well-documented, native Hawaiian plants like lava dock play important roles in supporting local ecosystems. As a native species, it’s likely to provide some benefits to native insects and contribute to the overall health of Hawaiian native plant communities.
The Bottom Line
Lava dock is definitely not a plant for every garden or every gardener. It’s a specialized species that requires specific conditions and responsible sourcing due to its potential rarity. However, for gardeners in appropriate climates who are passionate about native Hawaiian plants and have the right growing conditions, it can be a unique and meaningful addition to a specialized garden.
If you’re interested in growing lava dock, make sure you’re sourcing it from reputable native plant specialists who propagate their own stock. And remember – sometimes the most rewarding plants to grow are the ones that challenge us to create the perfect conditions for their success.
