North America Native Plant

Chickweed Oxytheca

Botanical name: Oxytheca caryophylloides

USDA symbol: OXCA3

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Chickweed Oxytheca: A Rare California Native Worth Protecting Meet chickweed oxytheca (Oxytheca caryophylloides), a charming little California native that’s flying under the radar of most gardeners – and for good reason. This delicate annual forb is one of those special plants that makes conservation-minded gardeners sit up and take notice, ...

Rare plant alert!

Region: Conservation status by state

Status: S3: Status is uncertain but is somewhere between the following rankings: 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 ⚘

Chickweed Oxytheca: A Rare California Native Worth Protecting

Meet chickweed oxytheca (Oxytheca caryophylloides), a charming little California native that’s flying under the radar of most gardeners – and for good reason. This delicate annual forb is one of those special plants that makes conservation-minded gardeners sit up and take notice, though it requires a thoughtful approach to cultivation.

What Makes Chickweed Oxytheca Special

Don’t let the common name fool you – this isn’t your typical garden chickweed! Chickweed oxytheca is a true California original, belonging to the buckwheat family. As an annual forb (that’s garden-speak for a non-woody flowering plant), it completes its entire life cycle in one growing season, producing delicate clusters of tiny white to pink flowers that seem to float above thread-like stems.

This petite native rarely grows more than a few inches tall, creating a low carpet of fine-textured foliage topped with airy flower clusters. While it may not have the showstopping presence of larger natives, its understated beauty lies in its delicate, almost ethereal appearance.

Where Chickweed Oxytheca Calls Home

Chickweed oxytheca is endemic to California, where it naturally occurs in the Central Valley and surrounding foothills. This limited geographic distribution makes it a true Golden State specialty – you won’t find this little gem growing wild anywhere else in the world.

A Word of Caution: Rarity Matters

Here’s something every responsible gardener needs to know: Chickweed oxytheca has a Global Conservation Status of S3, meaning it’s considered vulnerable to extinction. With typically only 21 to 100 known occurrences and between 3,000 to 10,000 individuals remaining in the wild, this is not a plant to collect casually from nature.

If you’re interested in growing this rare beauty, only obtain seeds or plants from reputable native plant nurseries that practice ethical sourcing. Never collect from wild populations – every plant counts when numbers are this low!

Growing Chickweed Oxytheca Successfully

This California native is adapted to the state’s Mediterranean climate and thrives in USDA hardiness zones 8-10. Here’s what you need to know:

Ideal Growing Conditions

  • Sunlight: Full sun exposure
  • Soil: Well-drained, even poor soils are fine
  • Water: Minimal irrigation once established; drought-tolerant
  • Climate: Mediterranean conditions with dry summers

Planting and Care Tips

Since chickweed oxytheca is an annual, you’ll need to replant each year or allow it to self-seed:

  • Timing: Direct seed in fall for spring bloom
  • Spacing: Scatter seeds lightly; this plant naturally forms loose colonies
  • Watering: Water gently during germination, then reduce irrigation
  • Maintenance: Minimal care required; avoid over-fertilizing

Perfect Garden Partners

Chickweed oxytheca works beautifully in specialized native plant gardens and restoration projects. It’s not suited for traditional ornamental landscapes but shines when planted alongside other small California natives like:

  • Native annual wildflowers
  • Small bunch grasses
  • Other rare or specialized natives

Supporting Local Wildlife

Despite its small stature, chickweed oxytheca pulls its weight in supporting native ecosystems. The tiny flowers attract small native bees and other beneficial insects, providing important nectar sources during its blooming period. In restoration settings, it helps create the complex plant communities that California’s native wildlife depends on.

Should You Grow Chickweed Oxytheca?

This plant is perfect for dedicated native plant enthusiasts who want to help conserve California’s rare flora. It’s not the right choice for gardeners seeking showy ornamentals or low-maintenance landscaping. However, if you’re passionate about conservation and have experience with native annuals, growing chickweed oxytheca from responsibly sourced seeds can be a meaningful way to support this vulnerable species.

Remember: with great rarity comes great responsibility. Only grow this plant if you’re committed to ethical sourcing and contributing to its conservation rather than its decline.

Chickweed Oxytheca

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

Oxytheca Nutt. - oxytheca

Species

Oxytheca caryophylloides Parry - chickweed oxytheca

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