North America Native Plant

Rainbow Iris

Botanical name: Iris hartwegii columbiana

USDA symbol: IRHAC

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Rainbow Iris: A Rare California Native Worth Protecting Meet the rainbow iris (Iris hartwegii columbiana), a delicate perennial that calls California home. This native beauty might not be the showiest plant in your garden center, but it’s got something special going for it – it’s a true Californian through and ...

Rare plant alert!

Region: Conservation status by state

Status: S4T2: Status is uncertain but is somewhere between the following rankings: Subspecies or variety is imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘

Rainbow Iris: A Rare California Native Worth Protecting

Meet the rainbow iris (Iris hartwegii columbiana), a delicate perennial that calls California home. This native beauty might not be the showiest plant in your garden center, but it’s got something special going for it – it’s a true Californian through and through, and frankly, it needs our help.

What Makes Rainbow Iris Special?

The rainbow iris is what botanists call a forb – basically a fancy way of saying it’s an herbaceous perennial without woody stems. Think of it as the gentle cousin in the iris family, perfectly adapted to California’s unique climate and ecosystems. As a native species, it has spent countless generations developing relationships with local wildlife, pollinators, and other plants that non-native species simply can’t replicate.

Where Does It Grow?

This particular iris is exclusively found in California, making it a true Golden State endemic. Its limited range means you won’t stumble across it in gardens across the country – it’s a regional treasure that belongs specifically to California’s diverse landscapes.

A Word of Caution: Rarity Matters

Here’s where things get serious for a moment. The rainbow iris has a conservation status of S4T2, which indicates this plant faces some level of conservation concern. This isn’t just garden talk – it means this species could be vulnerable in the wild. If you’re considering adding this iris to your garden, that’s wonderful! Native plants need champions. However, please ensure you source your plants from reputable nurseries that propagate them responsibly rather than collecting from wild populations.

Why Choose Rainbow Iris for Your Garden?

Beyond the conservation angle, there are practical reasons to consider this native iris:

  • It’s perfectly adapted to California’s climate, meaning less fussing with watering and soil amendments
  • Native plants typically require fewer pesticides and fertilizers
  • It supports local ecosystems and wildlife that have evolved alongside it
  • You’ll be growing something truly unique to your region

Growing Conditions and Care

While specific growing information for this particular subspecies is limited, most California native irises share similar preferences. They generally appreciate:

  • Well-draining soil (California natives often dislike soggy conditions)
  • Morning sun with some afternoon protection in hotter inland areas
  • Minimal summer water once established
  • Good air circulation

Garden Design Ideas

Rainbow iris works beautifully in:

  • Native plant gardens
  • Mediterranean-style landscapes
  • Rock gardens or naturalized areas
  • Wildlife gardens focused on supporting local species

The Bottom Line

The rainbow iris might not be the easiest plant to find, and it certainly isn’t the flashiest option at the nursery. But if you’re passionate about native plants and conservation, this little iris offers something invaluable: a chance to support a species that truly belongs in California’s landscape. Just remember to source it responsibly, and you’ll be doing your part to keep this regional treasure thriving for future generations.

Sometimes the best garden choices aren’t about what’s trendy or easy – they’re about what’s right for the place you call home.

Rainbow Iris

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Liliidae

Order

Liliales

Family

Iridaceae Juss. - Iris family

Genus

Iris L. - iris

Species

Iris hartwegii Baker - rainbow iris

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA