North America Native Plant

Hardham’s Evening Primrose

Botanical name: Camissonia hardhamiae

USDA symbol: CAHA15

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Hardham’s Evening Primrose: A Rare California Gem You Probably Shouldn’t Grow Meet Hardham’s evening primrose (Camissonia hardhamiae), one of California’s botanical mysteries that’s so rare, you’ll likely never encounter it in the wild—and definitely shouldn’t try to grow it in your garden. This little annual forb is the kind of ...

Rare plant alert!

Region: Conservation status by state

Status: S1Q: Status is uncertain but is somewhere between the following rankings: Uncertain taxonomy: ⚘ 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) ⚘

Hardham’s Evening Primrose: A Rare California Gem You Probably Shouldn’t Grow

Meet Hardham’s evening primrose (Camissonia hardhamiae), one of California’s botanical mysteries that’s so rare, you’ll likely never encounter it in the wild—and definitely shouldn’t try to grow it in your garden. This little annual forb is the kind of plant that makes botanists get excited and gardeners scratch their heads, wondering where on earth they’d even find seeds.

What Makes This Plant Special (and Elusive)

Hardham’s evening primrose is a native California annual that belongs to the evening primrose family. As a forb, it’s a soft-stemmed plant without woody growth—think of it as the botanical equivalent of a delicate wildflower that completes its entire life cycle in just one growing season.

This isn’t your typical garden center find. In fact, it’s got a Global Conservation Status of S1Q, which essentially means it’s rare enough that scientists are still trying to figure out exactly how rare it is. When a plant gets this kind of conservation status, it’s nature’s way of putting up a Handle with Care sign.

Where Does It Call Home?

Hardham’s evening primrose is found exclusively in California, making it a true Golden State endemic. However, even within California, its exact distribution remains somewhat of a mystery, which adds to its mystique and conservation concerns.

Should You Grow Hardham’s Evening Primrose?

Here’s where we need to have an honest conversation. While this rare native might sound intriguing, it’s not a plant you should be seeking out for your garden. Here’s why:

  • Its rarity status means it needs protection in its natural habitat, not cultivation in home gardens
  • Seeds and plants would be extremely difficult (if not impossible) to source responsibly
  • We simply don’t know enough about its specific growing requirements to cultivate it successfully
  • Growing rare plants from wild-collected material can harm wild populations

Better Native Alternatives for Your Garden

Instead of seeking out this rare gem, why not celebrate California’s evening primrose family with more readily available native alternatives? Consider these beautiful options that will give you similar evening primrose charm without the conservation concerns:

  • Desert evening primrose (Oenothera deltoides) – stunning white flowers that open at dusk
  • Mexican evening primrose (Oenothera speciosa) – pink blooms and spreading habit
  • Hooker’s evening primrose (Oenothera elata) – tall spikes of yellow flowers

The Bigger Picture: Why Rare Plants Matter

Plants like Hardham’s evening primrose remind us that California’s botanical diversity includes species hanging on by a thread. These rare natives often have very specific habitat requirements and limited distributions, making them vulnerable to habitat loss and climate change.

By choosing common native plants for our gardens and supporting conservation efforts for rare species like Camissonia hardhamiae, we can play our part in protecting California’s incredible plant heritage. Sometimes the best way to love a plant is to admire it from afar and let it thrive in its natural home.

What You Can Do Instead

If Hardham’s evening primrose has captured your imagination, channel that enthusiasm into supporting native plant conservation. Consider volunteering with local native plant societies, participating in habitat restoration projects, or simply choosing well-behaved native alternatives for your landscape.

Remember, every garden is an opportunity to support local ecosystems—and sometimes that means choosing the common natives that will actually thrive in your space over the rare ones that belong in specialized habitats.

Hardham’s Evening Primrose

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Myrtales

Family

Onagraceae Juss. - Evening Primrose family

Genus

Camissonia Link - suncup

Species

Camissonia hardhamiae P.H. Raven - Hardham's evening primrose

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