North America Native Plant

King’s Serpentweed

Botanical name: Tonestus kingii

USDA symbol: TOKI

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

King’s Serpentweed: A Rare Utah Treasure Worth Protecting in Your Garden If you’re looking to add a truly special native plant to your garden, King’s serpentweed (Tonestus kingii) might just be the hidden gem you’ve been searching for. This unassuming perennial forb carries the distinction of being one of Utah’s ...

Rare plant alert!

Region: Conservation status by state

Status: S3: 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 ⚘

King’s Serpentweed: A Rare Utah Treasure Worth Protecting in Your Garden

If you’re looking to add a truly special native plant to your garden, King’s serpentweed (Tonestus kingii) might just be the hidden gem you’ve been searching for. This unassuming perennial forb carries the distinction of being one of Utah’s most precious botanical treasures, though you’ll need to approach growing it with extra care and responsibility.

What Makes King’s Serpentweed Special

King’s serpentweed is a native perennial forb, meaning it’s an herbaceous plant that returns year after year without developing woody stems. As a member of the sunflower family (Asteraceae), it produces cheerful yellow composite flowers that add a splash of color to the landscape while supporting local pollinators.

What truly sets this plant apart isn’t just its beauty—it’s its rarity. King’s serpentweed holds a Global Conservation Status of S3, which translates to Vulnerable. This means it’s either very rare throughout its range or found only in restricted areas, making it vulnerable to disappearing entirely. With typically only 21 to 100 known occurrences worldwide, this plant is genuinely special.

Where King’s Serpentweed Calls Home

This remarkable plant is endemic to Utah, meaning you won’t find it growing naturally anywhere else in the world. Its entire global range is contained within the borders of the Beehive State, making it a true Utah native and a point of botanical pride for the region.

Why Consider Growing King’s Serpentweed

Despite its rarity—or perhaps because of it—King’s serpentweed offers several compelling reasons to include it in your native plant collection:

  • Conservation value: Growing this plant helps preserve a rare species
  • Unique Utah heritage: It’s a living piece of your state’s natural history
  • Pollinator support: Like other members of the sunflower family, it likely provides nectar and pollen for native bees and other beneficial insects
  • Low maintenance: As a Utah native, it’s naturally adapted to local growing conditions
  • Conversation starter: It’s sure to spark interesting discussions with fellow gardeners

The Responsible Approach to Growing King’s Serpentweed

Important: Because King’s serpentweed is classified as vulnerable, it’s crucial that you only obtain plants or seeds from reputable, ethical sources. Never collect from wild populations, as this could further threaten the species’ survival. Instead, work with:

  • Native plant societies
  • Botanical gardens with conservation programs
  • Certified native plant nurseries
  • Plant rescue operations (when habitat destruction is unavoidable)

Growing Conditions and Care

As a Utah native, King’s serpentweed is likely well-adapted to the state’s challenging growing conditions. While specific cultivation requirements aren’t well-documented due to its rarity, you can make educated assumptions based on Utah’s climate and typical native plant needs:

  • Sunlight: Full sun exposure
  • Soil: Well-draining soils, possibly rocky or sandy
  • Water: Low water requirements once established (drought tolerant)
  • Climate: Adapted to Utah’s temperature extremes

Perfect Garden Settings

King’s serpentweed would be most at home in:

  • Native plant gardens focused on Utah species
  • Rock gardens or xeriscaped areas
  • Conservation collections
  • Botanical demonstration gardens
  • Educational landscapes at nature centers or schools

A Plant with Purpose

Growing King’s serpentweed isn’t just about adding another species to your garden—it’s about participating in conservation. Every responsibly grown plant represents hope for this vulnerable species’ future. By cultivating King’s serpentweed, you’re helping ensure that future generations will be able to appreciate this unique piece of Utah’s natural heritage.

If you can’t locate ethically sourced King’s serpentweed, consider other native Utah plants that can provide similar ecological benefits while you continue your search. The key is supporting your local ecosystem while respecting the delicate balance that rare plants like King’s serpentweed require to survive and thrive.

King’s Serpentweed

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

Tonestus A. Nelson - serpentweed

Species

Tonestus kingii (D.C. Eaton) G.L. Nesom - King's serpentweed

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