North America Non-native Plant

San Francisco Nailwort

Botanical name: Paronychia franciscana

USDA symbol: PAFR

Life cycle: annual

Habit: forb

Native status: Non-native, reproduces and persists in the wild in the lower 48 states  

San Francisco Nailwort: A Little-Known Annual with Big Questions If you’ve stumbled across the name San Francisco nailwort (Paronychia franciscana), you might be scratching your head wondering what exactly this plant is all about. Don’t worry – you’re not alone! This annual forb is something of a botanical mystery, with ...

San Francisco Nailwort: A Little-Known Annual with Big Questions

If you’ve stumbled across the name San Francisco nailwort (Paronychia franciscana), you might be scratching your head wondering what exactly this plant is all about. Don’t worry – you’re not alone! This annual forb is something of a botanical mystery, with limited information available even to seasoned gardeners and plant enthusiasts.

What Is San Francisco Nailwort?

San Francisco nailwort belongs to the carnation family and is classified as a forb – essentially a non-woody flowering plant. Unlike its shrubby garden neighbors, this annual completes its entire life cycle in just one growing season. As a forb, it lacks significant woody tissue and keeps its growing points (those clever little buds that ensure survival) right at or below ground level.

Where Does It Come From?

Here’s where things get interesting: despite its San Francisco-inspired name, Paronychia franciscana is actually listed as a non-native species that has been introduced to the United States. It’s currently found growing wild in California, where it has managed to establish itself and reproduce without human assistance.

Should You Grow It?

This is where we hit a bit of a roadblock. While San Francisco nailwort isn’t classified as invasive or noxious, there’s surprisingly little information available about this particular species. Most of the details that would help you decide whether to include it in your garden – things like its appearance, growing requirements, and ecological benefits – remain unknown or poorly documented.

Given this uncertainty, you might want to consider some well-documented native alternatives that can provide similar benefits to your local ecosystem:

  • Native California wildflowers that support local pollinators
  • Indigenous annual forbs that thrive in your specific region
  • Well-researched native plants with known wildlife benefits

The Mystery of Growing Conditions

Unfortunately, specific information about San Francisco nailwort’s preferred growing conditions, USDA hardiness zones, and care requirements isn’t readily available. This makes it challenging to provide reliable guidance on how to successfully cultivate this plant.

If you’re determined to learn more about this species, consider reaching out to:

  • Local botanical gardens or native plant societies
  • University extension programs in California
  • Professional botanists familiar with the Paronychia genus

A Word of Caution

When dealing with poorly documented plant species, it’s always wise to proceed with caution. Before introducing any unfamiliar plant to your garden, especially a non-native one, consider the potential impacts on your local ecosystem. Sometimes the most responsible choice is to stick with well-known native species that provide proven benefits to local wildlife and pollinators.

The Bottom Line

While San Francisco nailwort remains something of an enigma in the gardening world, this uncertainty presents an opportunity to focus on the wealth of native plants that are well-documented, ecologically beneficial, and perfectly suited to your local growing conditions. Your garden – and your local ecosystem – will thank you for choosing plants with known benefits and clear growing requirements.

San Francisco Nailwort

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

Caryophyllales

Family

Caryophyllaceae Juss. - Pink family

Genus

Paronychia Mill. - nailwort

Species

Paronychia franciscana Eastw. - San Francisco nailwort

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