Thompson’s Iris: A Rare Pacific Coast Gem Worth Protecting
If you’re a native plant enthusiast with a passion for rare treasures, Thompson’s iris (Iris thompsonii) might just capture your heart. This uncommon perennial is one of the Pacific Coast’s best-kept secrets, offering gardeners a chance to grow something truly special while supporting native plant conservation.
What Makes Thompson’s Iris Special?
Thompson’s iris is a native herbaceous perennial that calls the coastal regions of California and Oregon home. As a member of the iris family, this charming forb produces the classic sword-like foliage and elegant blooms that gardeners love, but with the added appeal of being a true regional native.
You might also encounter this plant listed under its botanical synonym, Iris tenax ssp. thompsonii, as there’s some ongoing botanical discussion about its exact classification. Regardless of the naming debates, this Pacific Coast native deserves recognition in its own right.
Where Does Thompson’s Iris Grow?
This rare iris has a limited natural range, occurring only in California and Oregon. Its restricted distribution makes it a true regional specialty that connects your garden directly to the unique ecosystems of the Pacific Coast.
A Word of Caution: Rarity Matters
Before you rush out to find Thompson’s iris, there’s something important to know: this plant has a Global Conservation Status of S2S3, meaning it’s considered rare to uncommon in the wild. This makes Thompson’s iris a conservation priority, and any gardening decisions should be made thoughtfully.
If you’re interested in growing this special native, please ensure you source it only from reputable native plant nurseries that propagate their stock rather than collecting from wild populations. Never collect plants or seeds from natural areas.
Garden Appeal and Uses
Thompson’s iris fits beautifully into several garden styles:
- Native plant gardens showcasing Pacific Coast flora
- Rock gardens with well-draining conditions
- Specialty collections for iris enthusiasts
- Conservation gardens supporting rare species
As a forb, this iris lacks woody stems and dies back to ground level during dormancy, making it a perfect companion for other herbaceous natives and bulbs that follow similar seasonal patterns.
Supporting Pollinators and Wildlife
While specific data on Thompson’s iris wildlife benefits isn’t well-documented due to its rarity, iris species generally provide valuable resources for native pollinators. The flowers likely attract native bees, butterflies, and other beneficial insects, making this plant a contributor to local ecosystem health.
Growing Conditions and Care
Due to Thompson’s iris rarity, detailed growing information is limited. However, based on its Pacific Coast origins and relationship to other regional iris species, it likely prefers:
- Well-draining soil (essential for most iris species)
- Partial shade to filtered sunlight
- Mediterranean-style climate conditions
- Moderate water during growing season, drier conditions in summer
Given its native range in California and Oregon, Thompson’s iris probably thrives in USDA hardiness zones 7-9, though specific zone information isn’t well-established due to limited cultivation experience.
The Bottom Line
Thompson’s iris represents something special in the native plant world—a chance to grow a truly rare regional native while participating in conservation efforts. However, this opportunity comes with responsibility. Only pursue this plant if you can source it ethically and are committed to proper care.
For most gardeners interested in Pacific Coast natives, consider starting with more common regional iris species before seeking out rarities like Thompson’s iris. This approach helps build your native gardening skills while supporting the broader native plant movement.
If you do choose to grow Thompson’s iris, you’ll be joining a small community of dedicated native plant enthusiasts working to preserve Pacific Coast biodiversity, one garden at a time.
