North America Native Plant

Kenwood Marsh Checkerbloom

Botanical name: Sidalcea oregana valida

USDA symbol: SIORV

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Synonyms: Sidalcea spicata (Regel) Greene var. valida (Greene) Wiggins (SISPV)  âš˜  Sidalcea valida Greene (SIVA3)   

Kenwood Marsh Checkerbloom: A Rare California Native Worth Protecting Meet the Kenwood Marsh checkerbloom (Sidalcea oregana valida), one of California’s most endangered native wildflowers. This delicate perennial herb might not be a household name, but it represents something truly special in the world of native gardening—a plant so rare that ...

Rare plant alert!

Region: United States

Status: S5T1: 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) ⚘ Secure: At very low or no risk of extinction in the jurisdiction due to a very extensive range, abundant populations or occurrences, with little to no concern from declines or threats. ⚘ Endangered: In danger of extinction throughout all or a significant portion of its range. ⚘

Region: United States

Kenwood Marsh Checkerbloom: A Rare California Native Worth Protecting

Meet the Kenwood Marsh checkerbloom (Sidalcea oregana valida), one of California’s most endangered native wildflowers. This delicate perennial herb might not be a household name, but it represents something truly special in the world of native gardening—a plant so rare that every garden specimen could make a difference in its survival.

What Makes This Plant So Special?

The Kenwood Marsh checkerbloom is a perennial forb, meaning it’s a soft-stemmed plant that returns year after year. As part of the mallow family, it produces lovely pink to purple flowers arranged in tall spikes, creating a graceful vertical element that’s both beautiful and ecologically important.

You might also see this plant listed under its synonyms: Sidalcea spicata var. valida or simply Sidalcea valida. But regardless of what name you encounter, you’re looking at the same remarkable species.

Where Does It Come From?

This checkerbloom is a true California endemic, found naturally only in the Golden State. More specifically, it’s native to a very small area around Kenwood in Sonoma County, which explains both its common name and its precarious conservation status.

A Plant in Crisis: Understanding Its Endangered Status

Important Conservation Alert: The Kenwood Marsh checkerbloom carries an Endangered status in the United States, with a Global Conservation Status of S5T1. This means it’s at serious risk of extinction, making it one of our most vulnerable native plants.

If you’re considering adding this plant to your garden, please ensure you source it only from reputable native plant nurseries that propagate from ethically collected seeds or legally obtained plant material. Never collect plants or seeds from wild populations—every wild plant is crucial for the species’ survival.

Garden Potential and Landscape Role

While its rarity makes it challenging to obtain, the Kenwood Marsh checkerbloom can play a valuable role in specialized native plant gardens and restoration projects. Its tall flower spikes add vertical interest and likely provide nectar for native pollinators, particularly bees and butterflies that have co-evolved with California’s mallow species.

This plant is best suited for:

  • Dedicated native plant gardens
  • Conservation-focused landscapes
  • Educational gardens highlighting rare California flora
  • Habitat restoration projects (with proper permits and guidance)

Growing Conditions and Care

Given its limited range and endangered status, specific growing information for Kenwood Marsh checkerbloom is scarce. However, based on its native habitat and relationship to other Sidalcea species, it likely prefers:

  • Well-draining soil
  • Full sun to partial shade
  • Moderate water during growing season
  • USDA hardiness zones 8-10 (typical for its California range)

As a perennial herb, it will die back to the ground in winter and emerge again in spring. The exact height and spread are not well-documented, but related checkerblooms typically reach 2-4 feet tall.

Should You Plant It?

Here’s the honest answer: this plant isn’t for every gardener. Its endangered status means it should only be grown by dedicated native plant enthusiasts who can commit to proper care and are working with conservation-minded nurseries.

If you’re passionate about preserving California’s rarest flora and have experience with native plants, growing Kenwood Marsh checkerbloom could be a meaningful contribution to conservation efforts. However, if you’re new to native gardening or looking for a low-maintenance option, consider starting with more common Sidalcea species or other native California wildflowers.

Alternative Options

If you love the idea of checkerblooms but want something more readily available, consider these related native options:

  • Sidalcea malviflora (Dwarf checkerbloom)
  • Sidalcea oregana (Oregon checkerbloom)
  • Other native California mallows

The Bottom Line

The Kenwood Marsh checkerbloom represents both the beauty and fragility of California’s native flora. While it may not be the right choice for every garden, it serves as a powerful reminder of why native plant conservation matters. Whether you choose to grow this rare gem or simply appreciate its story, you’re connecting with something truly irreplaceable in the plant world.

Remember: if you do decide to grow this endangered species, source responsibly and consider it a privilege to help preserve one of California’s botanical treasures.

Kenwood Marsh Checkerbloom

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

Malvales

Family

Malvaceae Juss. - Mallow family

Genus

Sidalcea A. Gray - checkerbloom

Species

Sidalcea oregana (Nutt. ex Torr. & A. Gray) A. Gray - Oregon checkerbloom

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