North America Native Plant

Howell’s Pepperweed

Botanical name: Lepidium nitidum var. howellii

USDA symbol: LENIH

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Howell’s Pepperweed: A Rare California Native Worth Knowing Meet Howell’s pepperweed (Lepidium nitidum var. howellii), a little-known California native that’s as intriguing as it is elusive. This annual wildflower might not be the showstopper you’d expect to anchor your garden beds, but it represents something special in the world of ...

Rare plant alert!

Region: Conservation status by state

Status: S5T3?: Status is uncertain but is somewhere between the following rankings: Inexact rank: ⚘ Subspecies or variety is 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. ⚘ Secure: At very low or no risk of extinction in the jurisdiction due to a very extensive range, abundant populations or occurrences, with little to no concern from declines or threats. ⚘

Howell’s Pepperweed: A Rare California Native Worth Knowing

Meet Howell’s pepperweed (Lepidium nitidum var. howellii), a little-known California native that’s as intriguing as it is elusive. This annual wildflower might not be the showstopper you’d expect to anchor your garden beds, but it represents something special in the world of native plants – a unique variety that calls the Golden State home.

What Exactly Is Howell’s Pepperweed?

Howell’s pepperweed belongs to the mustard family and is classified as a forb – essentially a soft-stemmed plant that lacks the woody tissue you’d find in shrubs or trees. As an annual, this plant completes its entire life cycle in just one growing season, making it a fleeting but interesting addition to California’s native plant palette.

This particular variety is native to the lower 48 states, with its distribution focused in California. The plant carries the scientific name Lepidium nitidum var. howellii, named after botanist Thomas Howell who contributed significantly to Pacific Northwest botanical studies.

The Rarity Factor: Why This Matters

Here’s where things get interesting – and a bit concerning. Howell’s pepperweed has a Global Conservation Status of S5T3?, which indicates some level of conservation concern, though the exact status remains somewhat undefined. This rarity status is something every gardener should take seriously.

If you’re considering adding this plant to your garden, it’s crucial to source seeds or plants only from reputable native plant nurseries that can guarantee responsible collection practices. Never collect seeds or plants from wild populations, as this could further impact already vulnerable populations.

Should You Grow Howell’s Pepperweed?

The honest answer? Probably not, unless you’re a serious native plant enthusiast with specific conservation goals. Here’s why:

  • Limited availability due to its rarity status
  • Lack of detailed growing information for home gardeners
  • Annual nature means it won’t provide long-term garden structure
  • Potential conservation concerns with cultivation

Better Alternatives for Your California Native Garden

Instead of seeking out this rare variety, consider these more readily available California native annuals that can provide similar ecological benefits:

  • California poppies (Eschscholzia californica) – the state flower and a reliable annual
  • Clarkia species – beautiful annual wildflowers with excellent pollinator appeal
  • Lupinus species – nitrogen-fixing annuals that support soil health
  • Phacelia species – outstanding pollinator magnets

If You Do Choose to Grow It

Should you locate responsibly sourced Howell’s pepperweed, remember that as an annual, it will need to reseed itself or be replanted each year. Like most members of the mustard family, it likely prefers well-draining soils and full to partial sun exposure, though specific growing requirements for this variety remain poorly documented.

The best approach would be to contact local native plant societies or botanical gardens in California for guidance on cultivation practices and appropriate sourcing.

The Bigger Picture

Howell’s pepperweed serves as a reminder that California’s native plant diversity includes many species and varieties that exist quietly in the background of our more famous natives. While you might not plant this particular variety in your garden, knowing about plants like this helps us appreciate the incredible botanical heritage of California and the importance of preserving these unique varieties for future generations.

Sometimes the best way to support a rare native plant is simply to know it exists – and to choose more common natives that can provide similar ecological functions while leaving the rare ones to thrive in their natural habitats.

Howell’s Pepperweed

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Dilleniidae

Order

Capparales

Family

Brassicaceae Burnett - Mustard family

Genus

Lepidium L. - pepperweed

Species

Lepidium nitidum Nutt. - shining pepperweed

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