North America Native Plant

Siskiyou Clover

Botanical name: Trifolium siskiyouense

USDA symbol: TRSI4

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Trifolium wormskioldii Lehm. var. siskiyouense (J.M. Gillett) Isely (TRWOS)   

Siskiyou Clover: A Rare Native Gem for Pacific Northwest Gardens If you’re looking to add a touch of regional authenticity to your Pacific Northwest garden, Siskiyou clover might just be the hidden treasure you’ve been seeking. This charming native wildflower brings both ecological value and understated beauty to the right ...

Rare plant alert!

Region: Conservation status by state

Status: S3S4Q: Status is uncertain but is somewhere between the following rankings: Uncertain taxonomy: ⚘ Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘ 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 ⚘

Siskiyou Clover: A Rare Native Gem for Pacific Northwest Gardens

If you’re looking to add a touch of regional authenticity to your Pacific Northwest garden, Siskiyou clover might just be the hidden treasure you’ve been seeking. This charming native wildflower brings both ecological value and understated beauty to the right garden setting, though it comes with some important considerations for responsible gardeners.

What is Siskiyou Clover?

Siskiyou clover (Trifolium siskiyouense) is a perennial forb native to a very specific region of the American West. As a member of the legume family, this low-growing herbaceous plant produces the classic three-leaflet clover leaves and small, rounded flower heads that range from white to soft pink. Unlike its more common cousins, this clover has adapted to the unique conditions of its mountainous homeland.

Where Does It Grow Naturally?

This special clover calls the Siskiyou Mountains home, growing naturally only in southwestern Oregon and northwestern California. Its limited native range makes it a true regional specialty – think of it as the local artisan cheese of the plant world!

Important Conservation Note

Here’s where things get serious: Siskiyou clover has a Global Conservation Status of S3S4Q, indicating it’s considered rare and potentially vulnerable. This means if you’re interested in growing this beautiful native, you’ll want to source it responsibly from reputable native plant nurseries that propagate rather than wild-collect their plants. Never harvest seeds or plants from wild populations.

Why Grow Siskiyou Clover?

Despite its rarity concerns, there are compelling reasons to include this native in appropriate garden settings:

  • True regional native: Perfect for gardeners wanting authentic local flora
  • Pollinator magnet: The small flowers provide nectar for native bees, butterflies, and other beneficial insects
  • Low maintenance: Once established, it’s quite drought-tolerant and requires minimal care
  • Ground cover potential: Forms attractive low mats that can help suppress weeds
  • Nitrogen fixation: Like other legumes, it helps improve soil fertility

Best Garden Settings

Siskiyou clover isn’t meant for every garden, but it shines in specific situations:

  • Native plant gardens focused on regional species
  • Rock gardens with well-drained conditions
  • Naturalized meadow areas
  • Restoration projects in appropriate regions
  • Educational or botanical gardens showcasing rare natives

Growing Conditions and Care

This mountain native appreciates conditions that mirror its homeland:

  • Sunlight: Full sun to partial shade
  • Soil: Well-drained soils; tolerates poor, rocky conditions
  • Water: Moderate water needs; drought-tolerant once established
  • Climate: Best suited for USDA zones 7-9
  • Maintenance: Very low once established

Planting and Establishment Tips

Success with Siskiyou clover starts with proper planting:

  • Plant in spring after last frost danger passes
  • Ensure excellent drainage – this plant hates soggy feet
  • Space plants appropriately to allow for natural spreading
  • Water regularly during the first growing season to establish roots
  • Once established, reduce watering and let natural rainfall do most of the work
  • Allow some plants to go to seed if you want natural reproduction

The Bottom Line

Siskiyou clover represents both an opportunity and a responsibility. For gardeners in or near its native range who can source plants ethically, it offers a chance to grow something truly special while supporting regional biodiversity. Its rarity makes it unsuitable for casual gardening, but perfect for dedicated native plant enthusiasts who understand the importance of conservation-minded gardening.

If you can’t find responsibly-sourced Siskiyou clover, consider other native clovers in your region that can provide similar ecological benefits without the conservation concerns. Remember, the best native garden is one that supports local ecosystems while respecting the rarity and value of our most precious plant communities.

Siskiyou Clover

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

Fabales

Family

Fabaceae Lindl. - Pea family

Genus

Trifolium L. - clover

Species

Trifolium siskiyouense J.M. Gillett - Siskiyou clover

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