North America Native Plant

Metcalf Canyon Jewelflower

Botanical name: Streptanthus albidus albidus

USDA symbol: STALA

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Streptanthus glandulosus Hook. var. albidus (Greene) Jeps. (STGLA)   

Metcalf Canyon Jewelflower: A Rare California Native Worth Protecting If you’re a native plant enthusiast with a passion for conservation, you might have heard whispers about the Metcalf Canyon jewelflower (Streptanthus albidus albidus). This isn’t your typical backyard garden plant – it’s one of California’s most precious botanical treasures, and ...

Rare plant alert!

Region: United States

Status: S2T1: Status is uncertain but is somewhere between the following rankings: Subspecies or variety is 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) ⚘ 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) ⚘ Endangered: In danger of extinction throughout all or a significant portion of its range. ⚘

Region: United States

Metcalf Canyon Jewelflower: A Rare California Native Worth Protecting

If you’re a native plant enthusiast with a passion for conservation, you might have heard whispers about the Metcalf Canyon jewelflower (Streptanthus albidus albidus). This isn’t your typical backyard garden plant – it’s one of California’s most precious botanical treasures, and growing it comes with some serious responsibilities.

What Makes This Plant So Special?

The Metcalf Canyon jewelflower is a delicate annual or biennial forb that belongs to the mustard family. Don’t let the jewelflower name fool you into expecting flashy blooms – this plant’s beauty lies in its subtle charm and incredible rarity. With clusters of small, pale flowers and slender stems, it’s more about botanical significance than garden pizzazz.

A True California Endemic

This little beauty calls only one place home: Santa Clara County, California, specifically the Metcalf Canyon area. That’s right – nowhere else on Earth will you find this plant growing naturally. It’s what botanists call an endemic species, making it incredibly special and, unfortunately, incredibly vulnerable.

The Reality Check: This Plant is Endangered

Here’s where things get serious. The Metcalf Canyon jewelflower has an official conservation status that should make any gardener pause: it’s listed as Endangered in the United States. With a Global Conservation Status of S2T1, this plant is hanging on by a thread in the wild.

What does this mean for you as a gardener? If you’re considering adding this species to your garden, you absolutely must ensure any plant material comes from responsible, legal sources – never from wild populations. Better yet, consider supporting conservation efforts rather than growing it yourself.

Growing Conditions for the Brave (and Responsible)

If you do obtain this plant through proper conservation channels, here’s what you need to know about keeping it happy:

  • Climate: Thrives in USDA hardiness zones 9-10, preferring California’s Mediterranean climate
  • Soil: Requires well-drained soils, often found naturally on serpentine substrates
  • Water: Drought-tolerant once established, mimicking its natural dry habitat
  • Light: Prefers full sun to partial shade

Garden Role and Design Ideas

This isn’t a plant for mass plantings or showy displays. If you’re growing Metcalf Canyon jewelflower, it’s likely going in a specialized native plant collection, rock garden, or conservation-focused landscape. Think of it as a living museum piece rather than typical garden fare.

Supporting Pollinators

Despite its small stature, this jewelflower does its part for local ecosystems by attracting small native bees and other pollinators. Every bloom contributes to the complex web of relationships that keep California’s native habitats functioning.

The Bottom Line

Should you plant Metcalf Canyon jewelflower? That’s a complex question. If you’re deeply committed to native plant conservation, have experience with rare species, and can guarantee responsible sourcing, it might have a place in your specialized collection. However, for most gardeners, supporting conservation organizations working to protect this species in the wild might be more impactful than trying to grow it at home.

Consider this: there are plenty of other beautiful, less vulnerable California natives that can provide similar ecological benefits without the conservation concerns. Sometimes the most loving thing we can do for a rare plant is simply let it be.

Remember, with great botanical beauty comes great responsibility – and in the case of the Metcalf Canyon jewelflower, that responsibility is enormous.

Metcalf Canyon Jewelflower

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Dilleniidae

Order

Capparales

Family

Brassicaceae Burnett - Mustard family

Genus

Streptanthus Nutt. - twistflower

Species

Streptanthus albidus Greene - Metcalf Canyon jewelflower

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