North America Native Plant

Spiked Western Rosinweed

Botanical name: Calycadenia spicata

USDA symbol: CASP2

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Hemizonia spicata Greene (HESP7)   

Spiked Western Rosinweed: A Golden Gem for California Native Gardens If you’re looking to add a splash of sunshine to your California native garden while supporting local wildlife, let me introduce you to spiked western rosinweed (Calycadenia spicata). This charming annual wildflower might not have the flashiest name, but it ...

Rare plant alert!

Region: Conservation status by state

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

Spiked Western Rosinweed: A Golden Gem for California Native Gardens

If you’re looking to add a splash of sunshine to your California native garden while supporting local wildlife, let me introduce you to spiked western rosinweed (Calycadenia spicata). This charming annual wildflower might not have the flashiest name, but it packs a punch when it comes to ecological value and understated beauty.

What is Spiked Western Rosinweed?

Spiked western rosinweed is a true California native, belonging to the sunflower family. You might also see it listed under its scientific synonym, Hemizonia spicata Greene, in older gardening resources. As an annual forb, this herbaceous plant completes its entire life cycle in one growing season, making it a delightful addition to wildflower meadows and naturalized landscapes.

Where Does It Call Home?

This golden beauty is endemic to California, meaning you won’t find it growing wild anywhere else in the world. It thrives in the state’s grasslands and oak woodlands, perfectly adapted to the Mediterranean climate that defines much of the Golden State.

Why Your Garden Will Love This Plant

Spiked western rosinweed brings several wonderful qualities to your landscape:

  • Pollinator magnet: Those cheerful yellow flowers are like a beacon for native bees, butterflies, and other beneficial insects
  • Low maintenance: Once established, it’s remarkably drought tolerant
  • Self-sufficient: As an annual, it readily self-seeds, creating natural colonies year after year
  • Authentic beauty: Nothing beats the authentic look of plants that truly belong in your local ecosystem

What to Expect

Picture small, bright yellow composite flowers arranged in distinctive spikes rising above narrow, linear leaves. The plant typically grows in an upright form, creating vertical interest in your garden while maintaining a naturalistic appearance that blends beautifully with other native wildflowers.

Perfect Garden Settings

Spiked western rosinweed shines in:

  • Native California gardens
  • Drought-tolerant landscapes
  • Wildflower meadows
  • Naturalized areas
  • Pollinator gardens

Growing Conditions and Care

This adaptable native thrives in USDA hardiness zones 8-10, which covers most of California’s diverse climate regions. Here’s what it needs to flourish:

  • Sunlight: Full sun exposure
  • Soil: Well-draining soils (it’s not picky about soil type)
  • Water: Drought tolerant once established, mimicking California’s natural rainfall patterns

Planting and Care Tips

Growing spiked western rosinweed is refreshingly straightforward:

  • Direct seed in fall to align with natural rainfall patterns
  • Provide minimal water after establishment
  • Allow plants to complete their life cycle and drop seeds for next year’s display
  • Avoid overwatering, which can lead to problems in this drought-adapted species

An Important Conservation Note

Here’s something every responsible gardener should know: spiked western rosinweed has a Global Conservation Status of S3?, which indicates some uncertainty about its conservation status. This makes it even more important to choose your plants wisely. If you decide to grow this beautiful native, please ensure you’re purchasing from reputable native plant nurseries that use responsibly sourced, locally appropriate genetic material. Never collect seeds or plants from wild populations.

The Bottom Line

Spiked western rosinweed offers California gardeners a wonderful opportunity to support native biodiversity while enjoying low-maintenance beauty. Its cheerful flowers, pollinator appeal, and authentic California character make it a valuable addition to native plant gardens. Just remember to source your plants responsibly and let this charming annual work its magic naturally in your landscape.

By choosing natives like spiked western rosinweed, you’re not just creating a beautiful garden – you’re participating in the conservation of California’s unique plant heritage. And really, what could be more rewarding than that?

Spiked Western Rosinweed

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Asterales

Family

Asteraceae Bercht. & J. Presl - Aster family

Genus

Calycadenia DC. - western rosinweed

Species

Calycadenia spicata (Greene) Greene - spiked western rosinweed

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