North America Native Plant

Loch Lomond Eryngo

Botanical name: Eryngium constancei

USDA symbol: ERCO39

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Loch Lomond Eryngo: A Rare Wetland Gem Worth Protecting If you’re drawn to unique, spiky plants that look like they belong in a fairy tale, the Loch Lomond eryngo might catch your eye. But before you start planning where to plant this distinctive beauty, there’s something important you need to ...

Rare plant alert!

Region: United States

Status: S1: Status is uncertain but is somewhere between the following rankings: Critically Imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 5 or fewer occurrences or very few remaining individuals (<1,000) ⚘ Endangered: In danger of extinction throughout all or a significant portion of its range. ⚘

Region: United States

Loch Lomond Eryngo: A Rare Wetland Gem Worth Protecting

If you’re drawn to unique, spiky plants that look like they belong in a fairy tale, the Loch Lomond eryngo might catch your eye. But before you start planning where to plant this distinctive beauty, there’s something important you need to know: this remarkable native is one of California’s rarest plants.

What Makes This Plant Special?

Loch Lomond eryngo (Eryngium constancei) is a perennial forb that produces striking blue-green flower heads surrounded by spiky, thistle-like bracts. Unlike its woody cousins, this herbaceous plant dies back to ground level each year, emerging fresh each growing season with its characteristic architectural form.

This isn’t just any garden-variety plant – it’s a true California endemic, meaning it grows nowhere else on Earth naturally. Its unique appearance and extreme rarity make it a botanical treasure that deserves our respect and protection.

Where Does It Call Home?

This special eryngo is native exclusively to California, with its entire natural range centered around the Clear Lake area in Lake County. The plant gets its common name from the historic Loch Lomond area, highlighting just how geographically limited this species really is.

A Plant in Crisis

Here’s where things get serious: Loch Lomond eryngo has a Global Conservation Status of S1, meaning it’s critically imperiled. With typically five or fewer known occurrences and very few remaining individuals (fewer than 1,000), this plant is classified as Endangered in the United States.

This rarity status means that if you’re interested in growing this plant, you absolutely must source it responsibly. Only work with reputable native plant societies or conservation organizations that can verify the plant material wasn’t collected from wild populations.

Wetland Specialist

One reason this plant is so rare is its very specific habitat needs. Loch Lomond eryngo is classified as an Obligate Wetland plant in both California’s arid regions and mountainous areas, meaning it almost always occurs in wetlands and requires consistently moist to wet conditions.

This isn’t a plant that will thrive in your average garden bed. It needs:

  • Consistently moist to saturated soils
  • Full sun to partial shade
  • Wetland or bog-like conditions
  • USDA hardiness zones 9-10

Garden Role and Design Potential

If you have the right wetland conditions and can source this plant responsibly, Loch Lomond eryngo can serve as a fascinating specimen in:

  • Native wetland gardens
  • Bog or marsh gardens
  • Conservation-focused landscapes
  • Rare plant collections

Its spiky, architectural form provides unique texture and visual interest, while its blue-green flower heads attract specialized native pollinators, including native bees and other small beneficial insects.

Growing This Rare Beauty

Successfully cultivating Loch Lomond eryngo requires replicating its natural wetland habitat. This means maintaining consistently wet soils – think more like a bog than a regular garden bed. The plant typically grows best in full sun but can tolerate some partial shade.

Given its endangered status and specific habitat needs, this plant is extremely challenging to grow outside its natural range. Even experienced native plant gardeners may struggle to provide the precise conditions it requires.

The Conservation Connection

Rather than trying to grow this rare plant, many gardeners choose to support its conservation in other ways. Consider visiting its natural habitat (respectfully and without disturbing the plants), supporting organizations working to protect it, or choosing other native wetland plants that provide similar ecological benefits without the conservation concerns.

Should You Plant It?

The honest answer? Probably not, unless you’re an experienced native plant specialist with perfect wetland conditions and access to responsibly propagated material. This plant’s extreme rarity and specific habitat needs make it better suited for conservation efforts than casual gardening.

If you’re drawn to unique, spiky native plants, consider other California natives like native thistles or other Eryngium species that aren’t endangered. You’ll get similar aesthetic appeal while supporting conservation by leaving the rarest plants to the specialists.

Sometimes the best way to love a plant is to admire it from afar and support the efforts to keep it thriving in its natural home.

Loch Lomond Eryngo

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Apiales

Family

Apiaceae Lindl. - Carrot family

Genus

Eryngium L. - eryngo

Species

Eryngium constancei Sheikh - Loch Lomond eryngo

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