North America Native Plant

San Diego Tarweed

Botanical name: Hemizonia paniculata

USDA symbol: HEPA6

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Deinandra paniculata (A. Gray) Davidson & Moxley (DEPA16)   

San Diego Tarweed: A Golden Native Annual for California Gardens Meet San Diego tarweed (Hemizonia paniculata), a charming native California annual that’s been quietly brightening up the Golden State’s landscapes long before European settlers arrived. This delightful wildflower might not be the showiest plant in your garden, but it offers ...

Rare plant alert!

Region: Conservation status by state

Status: S3S4: 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 ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘

San Diego Tarweed: A Golden Native Annual for California Gardens

Meet San Diego tarweed (Hemizonia paniculata), a charming native California annual that’s been quietly brightening up the Golden State’s landscapes long before European settlers arrived. This delightful wildflower might not be the showiest plant in your garden, but it offers something special for gardeners who appreciate understated beauty and ecological value.

What Is San Diego Tarweed?

San Diego tarweed is a native annual forb – essentially a non-woody flowering plant that completes its entire life cycle in one growing season. You might also encounter it under its scientific synonym Deinandra paniculata, but don’t let the name changes confuse you – it’s the same wonderful plant.

As its common name suggests, this species calls southern California home, specifically thriving in California’s Mediterranean climate. It’s perfectly adapted to the region’s wet winters and dry summers, making it an excellent choice for water-wise gardening.

Why Consider San Diego Tarweed for Your Garden?

Before you decide whether this plant belongs in your landscape, here are the key reasons gardeners love (or sometimes overlook) San Diego tarweed:

The Bright Spots

  • True California native: Perfect for authentic native plant gardens
  • Drought champion: Thrives with minimal water once established
  • Pollinator magnet: Attracts native bees, butterflies, and beneficial insects
  • Low maintenance: Self-seeds readily for next year’s display
  • Aromatic foliage: Adds a pleasant herbal scent to your garden

Things to Consider

  • Conservation status: This plant has a somewhat limited distribution and should be grown from responsibly sourced seeds
  • Annual nature: Dies back each year, though it typically self-seeds
  • Regional specificity: Best suited for southern California’s climate zones

Garden Design and Landscape Role

San Diego tarweed shines in naturalized wildflower gardens and native plant landscapes. Its branched clusters of small, bright yellow daisy-like flowers create a delicate, airy texture that works beautifully as:

  • Understory plantings in oak woodlands
  • Slope stabilization in erosion-prone areas
  • Filler plants in drought-tolerant perennial borders
  • Wildlife habitat gardens focused on supporting native pollinators

The plant’s growth habit as a forb means it stays relatively low and herbaceous, making it ideal for mixing with native grasses and other wildflowers rather than serving as a standalone specimen.

Growing Conditions and Care

San Diego tarweed is refreshingly easy to grow if you can provide the right conditions:

Ideal Growing Conditions

  • Sunlight: Full sun (6+ hours daily)
  • Soil: Well-draining soils; adaptable to various soil types
  • Water: Drought tolerant once established; prefers dry summers
  • Climate: USDA hardiness zones 9-11 (Mediterranean climate)
  • Wetland status: Facultative upland (usually grows in non-wetland areas)

Planting and Care Tips

Since San Diego tarweed is an annual, your approach will differ from perennial natives:

  • Seeding: Direct seed in fall for spring germination and bloom
  • Watering: Provide regular water during establishment, then reduce significantly
  • Maintenance: Minimal care needed; allow plants to self-seed for next year
  • Harvesting seeds: Collect seeds in late summer if you want to control where they germinate

A Responsible Choice for Native Gardeners

Given San Diego tarweed’s conservation status and limited natural range, it’s important to source seeds or plants from reputable native plant societies or nurseries that practice ethical wild collection. This ensures you’re supporting conservation efforts rather than potentially impacting wild populations.

For southern California gardeners passionate about creating authentic native habitats, San Diego tarweed offers a wonderful opportunity to support local ecology while enjoying a charming, low-maintenance annual that truly belongs in your landscape. Just remember – this isn’t a plant for everywhere, but in the right California garden, it’s absolutely golden.

San Diego Tarweed

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

Hemizonia DC. - tarweed

Species

Hemizonia paniculata A. Gray - San Diego tarweed

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