North America Native Plant

Pricklyseed Pygmyweed

Botanical name: Crassula viridis

USDA symbol: CRVI6

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Tillaea viridis S. Watson (TIVI)  âš˜  Tillaeastrum viride (S. Watson) Britton (TIVI2)   

Pricklyseed Pygmyweed: A Tiny Native Treasure Worth Protecting Meet one of North America’s most understated native plants: pricklyseed pygmyweed (Crassula viridis). This diminutive annual succulent might not win any beauty contests, but it’s a fascinating example of how plants adapt to harsh desert conditions. If you’re looking to support native ...

Rare plant alert!

Region: Conservation status by state

Status: S1S3: Status is uncertain but is somewhere between the following rankings: 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) ⚘ 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 ⚘

Pricklyseed Pygmyweed: A Tiny Native Treasure Worth Protecting

Meet one of North America’s most understated native plants: pricklyseed pygmyweed (Crassula viridis). This diminutive annual succulent might not win any beauty contests, but it’s a fascinating example of how plants adapt to harsh desert conditions. If you’re looking to support native biodiversity and don’t mind plants that whisper rather than shout, this little gem deserves your attention.

What Exactly Is Pricklyseed Pygmyweed?

Pricklyseed pygmyweed is a tiny annual forb in the stonecrop family, growing just 1-4 inches tall and wide. Think of it as nature’s bonsai – perfectly formed but naturally miniature. Its small, scale-like leaves form neat little rosettes, and if you look closely (and we mean really closely), you’ll spot its minute white or pinkish flowers that appear in spring.

You might also see this plant listed under its former scientific names: Tillaea viridis or Tillaeastrum viride. Botanists love to shuffle plant names around, but the plant itself remains charmingly consistent.

Where Does It Call Home?

This native plant has a surprisingly limited range, naturally occurring only in Arizona and Idaho – quite the geographic split! It’s perfectly adapted to the desert Southwest’s challenging conditions, thriving in rocky washes, disturbed soils, and other spots where most plants would throw in the towel.

A Conservation Concern

Here’s where things get important: pricklyseed pygmyweed has a Global Conservation Status of S1S3, meaning it’s considered rare to uncommon throughout its range. This isn’t a plant you’ll stumble across at your local nursery, and that’s exactly why it needs our attention.

If you’re interested in growing this species, please only use seeds or plants from reputable sources that collect responsibly and legally. Never collect from wild populations – these small communities need every individual they can get.

Garden Appeal and Design Role

Let’s be honest – pricklyseed pygmyweed isn’t going to be your garden’s showstopper. Its appeal lies in its subtle beauty and ecological significance rather than dramatic visual impact. This plant works best in:

  • Native plant collections and botanical gardens
  • Rock gardens designed for desert species
  • Conservation landscapes focused on rare species
  • Educational gardens highlighting regional biodiversity

Growing Conditions and Care

If you decide to grow pricklyseed pygmyweed, you’ll need to recreate its natural desert habitat. This means:

  • Excellent drainage: Think sandy, rocky, or gravelly soil that drains immediately after watering
  • Full sun: At least 6-8 hours of direct sunlight daily
  • Minimal water: Once established, water sparingly – this plant is drought-adapted
  • USDA zones 8-10: It needs warm temperatures and can’t handle hard freezes

Planting and Care Tips

Growing pricklyseed pygmyweed successfully requires patience and a light touch:

  • Start from seed in fall or early spring when temperatures are mild
  • Scatter seeds on the soil surface – don’t bury them deeply
  • Keep soil lightly moist until germination, then reduce watering dramatically
  • Expect plants to complete their lifecycle quickly – remember, this is an annual
  • Allow plants to self-seed for future generations

Wildlife and Pollinator Benefits

While small, pricklyseed pygmyweed’s tiny flowers can provide nectar for small native bees and other minute pollinators. Its seeds may also feed small birds and insects, contributing to the complex web of desert ecology.

Should You Grow It?

Pricklyseed pygmyweed isn’t for every gardener, but it’s perfect for those who:

  • Want to support conservation of rare native species
  • Enjoy subtle, understated plants
  • Are creating authentic desert or rock gardens
  • Appreciate the challenge of growing uncommon species

Remember, with great rarity comes great responsibility. If you choose to grow this species, do so as a conservation effort rather than a typical garden addition. Every responsibly grown plant helps ensure that future generations can appreciate this humble but important piece of our native plant heritage.

Sometimes the smallest plants teach us the biggest lessons about resilience, adaptation, and the quiet beauty of our native landscapes. Pricklyseed pygmyweed may be tiny, but its story – and its conservation – is mighty important.

Pricklyseed Pygmyweed

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

Rosales

Family

Crassulaceae J. St.-Hil. - Stonecrop family

Genus

Crassula L. - pygmyweed

Species

Crassula viridis (S. Watson) Bywater & Wickens - pricklyseed pygmyweed

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