North America Native Plant

Krukeberg’s Jewelflower

Botanical name: Streptanthus morrisonii kruckebergii

USDA symbol: STMOK

Life cycle: biennial

Habit: forb

Native status: Native to the lower 48 states  

Krukeberg’s Jewelflower: A Rare California Native Worth Protecting If you’re passionate about native plants and conservation, you might have stumbled across the intriguing Krukeberg’s jewelflower (Streptanthus morrisonii kruckebergii). This little-known California native is one of those special plants that makes you feel like you’ve discovered a hidden gem – and ...

Rare plant alert!

Region: Conservation status by state

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) ⚘

Krukeberg’s Jewelflower: A Rare California Native Worth Protecting

If you’re passionate about native plants and conservation, you might have stumbled across the intriguing Krukeberg’s jewelflower (Streptanthus morrisonii kruckebergii). This little-known California native is one of those special plants that makes you feel like you’ve discovered a hidden gem – and in many ways, you have.

What Makes This Plant Special?

Krukeberg’s jewelflower is a biennial forb, meaning it completes its life cycle over two years and lacks the woody stems you’d find on shrubs or trees. As part of the jewelflower family, it belongs to the mustard family (Brassicaceae), which gives you a hint about its delicate, four-petaled flowers that are characteristic of this plant group.

This particular subspecies is named after botanist Arthur Kruckeberg, who was renowned for his work with plants that grow in challenging soil conditions. That naming choice gives us a clue about where this plant likes to call home!

Where Does It Grow?

Krukeberg’s jewelflower is exclusively found in California, making it a true Golden State endemic. This means you won’t find it growing wild anywhere else in the world – pretty special, right?

A Word of Caution: This Plant is Rare

Here’s where things get serious. Krukeberg’s jewelflower has a Global Conservation Status of S2T1, which places it in the critically imperiled category. This means the plant faces a very high risk of extinction, with very few populations remaining in the wild.

If you’re considering adding this plant to your garden, please only obtain it through responsibly sourced material from reputable native plant nurseries or conservation organizations. Never collect plants or seeds from wild populations – this could further threaten an already vulnerable species.

Should You Grow Krukeberg’s Jewelflower?

The answer is nuanced. While growing rare natives can be incredibly rewarding and supports conservation efforts, this particular plant comes with significant responsibility. Here’s what to consider:

  • Conservation value: Growing rare natives helps preserve genetic diversity and can serve as insurance populations
  • Educational opportunity: Having rare plants in your garden creates talking points about conservation
  • Sourcing challenges: Finding responsibly propagated material may be difficult
  • Limited information: Care requirements are not well-documented, making successful cultivation challenging

Growing Conditions and Care

Unfortunately, detailed growing information for this specific subspecies is quite limited due to its rarity. However, based on its classification as a biennial forb and its membership in the jewelflower group, here’s what we can infer:

  • As a biennial, it will grow vegetatively in its first year and flower in its second year before completing its lifecycle
  • Like other jewelflowers, it likely prefers well-draining soils and may tolerate challenging growing conditions
  • Being a California native, it’s probably adapted to Mediterranean climate conditions with dry summers and mild, wet winters
  • Full sun to partial shade is likely preferred, following patterns of related species

The Bigger Picture

While Krukeberg’s jewelflower might not be the easiest addition to your native plant garden, it represents something important: the incredible diversity of California’s flora and the urgent need for conservation. Sometimes the most valuable plants aren’t the showiest ones – they’re the ones that remind us what we stand to lose.

If you’re passionate about rare plant conservation and have experience with challenging natives, this could be a meaningful addition to your garden. Just remember to source responsibly and consider it a living piece of California’s natural heritage that you’re helping to preserve.

For most gardeners interested in supporting native plants and pollinators, consider starting with more common California natives that offer similar ecological benefits while being more readily available and easier to establish. Every native plant in your garden makes a difference, regardless of how rare or common it might be.

Krukeberg’s 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 morrisonii F.W. Hoffm. - Morrison's jewelflower

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