North America Native Plant

Mt. Diablo Buckwheat

Botanical name: Eriogonum truncatum

USDA symbol: ERTR11

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Mt. Diablo Buckwheat: A Rare California Treasure Worth Protecting If you’re passionate about native plants and conservation, Mt. Diablo buckwheat (Eriogonum truncatum) might just capture your heart—though it’s definitely not your average garden center find. This little-known California native is one of those special plants that makes you feel like ...

Rare plant alert!

Region: Conservation status by state

Status: S2: Status is uncertain but is somewhere between the following rankings: 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) ⚘

Mt. Diablo Buckwheat: A Rare California Treasure Worth Protecting

If you’re passionate about native plants and conservation, Mt. Diablo buckwheat (Eriogonum truncatum) might just capture your heart—though it’s definitely not your average garden center find. This little-known California native is one of those special plants that makes you feel like you’re part of something bigger when you grow it.

What Makes Mt. Diablo Buckwheat Special?

Mt. Diablo buckwheat is an annual forb, meaning it completes its entire life cycle in one growing season and lacks woody stems. Don’t let its humble status fool you, though—this plant packs a lot of charm into its compact form. As a member of the buckwheat family, it produces clusters of small, delicate flowers that range from white to soft pink, creating a subtle but lovely display in late spring and early summer.

A True California Native

This buckwheat species is native to the lower 48 states, but its heart belongs entirely to California. It’s what botanists call endemic—found naturally nowhere else on Earth except in the Golden State. The plant has a very limited range, primarily centered around the Mount Diablo area and a few surrounding locations in central California.

Important Conservation Alert

Here’s where things get serious: Mt. Diablo buckwheat has a Global Conservation Status of S2, which means it’s considered Imperiled. With typically only 6 to 20 known occurrences and an estimated 1,000 to 3,000 individuals remaining in the wild, this plant is genuinely rare. If you’re considering adding it to your garden, please ensure you source seeds or plants only from reputable native plant nurseries that practice responsible collection methods—never from wild populations.

Garden Role and Design Potential

Mt. Diablo buckwheat shines in specialized gardens where conservation and native plant appreciation take center stage. It’s perfect for:

  • Conservation gardens focused on rare California species
  • Rock gardens with excellent drainage
  • Native plant collections
  • Xerophytic (drought-adapted) garden designs
  • Educational gardens highlighting biodiversity

While it won’t be the showstopper of your landscape, its quiet beauty and conservation significance make it a meaningful addition for dedicated native plant enthusiasts.

Growing Conditions and Care

Mt. Diablo buckwheat thrives in USDA hardiness zones 9-10, reflecting California’s Mediterranean climate. Here’s what this little treasure needs to flourish:

  • Sun exposure: Full sun is essential
  • Soil: Well-draining soil is absolutely critical—think sandy or rocky conditions
  • Water: Minimal water once established; overwatering is often fatal
  • Climate: Prefers dry summers and mild, wet winters

Planting and Care Tips

Growing Mt. Diablo buckwheat requires a gentle touch and patience:

  • Direct seeding is often more successful than transplanting
  • Sow seeds in fall for natural winter stratification
  • Provide excellent drainage—consider raised beds or slopes
  • Water sparingly and only during establishment
  • Allow natural reseeding for sustainable populations
  • Avoid fertilizers, which can harm this adapted-to-poor-soils species

Benefits to Pollinators and Wildlife

Despite its small stature, Mt. Diablo buckwheat pulls its weight in supporting local ecosystems. The flowers attract small native bees and other beneficial insects, providing nectar during its blooming period. As with many buckwheats, the seeds likely provide food for small birds and other wildlife, though specific data for this rare species is limited.

Should You Grow Mt. Diablo Buckwheat?

If you’re a conservation-minded gardener with the right growing conditions and access to responsibly sourced material, absolutely! Growing rare native plants like Mt. Diablo buckwheat serves as both a form of ex-situ conservation and a way to connect with California’s unique botanical heritage. Just remember that this isn’t a plant for casual gardeners—it requires specific conditions and a commitment to conservation ethics.

By choosing to grow Mt. Diablo buckwheat, you’re not just adding a plant to your garden; you’re becoming a guardian of one of California’s rarest botanical treasures. And really, isn’t that the kind of gardening story worth telling?

Mt. Diablo Buckwheat

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Caryophyllidae

Order

Polygonales

Family

Polygonaceae Juss. - Buckwheat family

Genus

Eriogonum Michx. - buckwheat

Species

Eriogonum truncatum Torr. & A. Gray - Mt. Diablo buckwheat

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