North America Native Plant

Smooth-seed Pygmyweed

Botanical name: Crassula solieri

USDA symbol: CRSO5

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Synonyms: Crassula solierii (C. Gay) Meigen, database artifact (CRSO4)  âš˜  Tillaea solierii C. Gay (TISO)   

Smooth-Seed Pygmyweed: A Tiny Native Treasure for Wetland Gardens Meet Smooth-Seed Pygmyweed (Crassula solieri), one of nature’s most unassuming little gems. This petite native annual might not win any beauty contests, but it’s got character in spades and plays an important role in America’s wetland ecosystems. If you’re looking to ...

Smooth-Seed Pygmyweed: A Tiny Native Treasure for Wetland Gardens

Meet Smooth-Seed Pygmyweed (Crassula solieri), one of nature’s most unassuming little gems. This petite native annual might not win any beauty contests, but it’s got character in spades and plays an important role in America’s wetland ecosystems. If you’re looking to create an authentic native wetland garden or simply curious about our continent’s diverse plant life, this tiny succulent deserves a spot on your radar.

What Makes Smooth-Seed Pygmyweed Special?

Don’t let the name fool you – while it’s called a pygmyweed, this little plant packs a lot of ecological value into its small stature. As an annual forb (that’s garden-speak for a non-woody flowering plant), Smooth-Seed Pygmyweed completes its entire life cycle in just one growing season. It’s a true American native, naturally occurring across six states in the western and central United States.

Where You’ll Find It Growing Wild

Smooth-Seed Pygmyweed has quite the range for such a small plant! You can find it growing naturally in California, Montana, Nevada, Oregon, Texas, and Wyoming. This distribution tells us it’s pretty adaptable to different climates, though it has one very specific requirement: water, and lots of it.

The Water-Loving Lifestyle

Here’s where things get interesting – this little plant is practically glued to wet places. Its wetland status varies by region, but the message is clear: Smooth-Seed Pygmyweed loves moisture. In some areas, it’s considered an obligate wetland plant, meaning you’ll almost always find it in soggy conditions. In other regions, it’s a facultative wetland species that usually prefers wet feet but can occasionally tolerate drier spots.

This water dependency makes it perfect for:

  • Bog gardens and constructed wetlands
  • Rain gardens in appropriate climates
  • Native plant collections focused on wetland species
  • Restoration projects in wetland areas

Should You Grow Smooth-Seed Pygmyweed?

The honest answer? It depends on what you’re after. This isn’t your typical garden showstopper – think of it more as an ecological specialist. If you’re passionate about native plants, creating habitat, or have a naturally wet area in your garden that needs authentic native vegetation, Smooth-Seed Pygmyweed could be perfect.

Reasons to consider it:

  • True native species supporting local ecosystems
  • Perfect for specialized wetland garden projects
  • Low-maintenance once established in proper conditions
  • Educational value for learning about native wetland plants
  • Part of authentic regional plant communities

Reasons it might not be right for you:

  • Very specific moisture requirements
  • Annual lifecycle means replanting or reseeding needed
  • Minimal ornamental appeal
  • Not suitable for typical garden beds

Growing Smooth-Seed Pygmyweed Successfully

If you’ve decided this little native is worth a try, here’s how to give it the best shot at success:

Location, Location, Location: This plant needs consistent moisture – think bog-like conditions rather than your typical garden bed. Natural low spots, areas with poor drainage, or constructed wetland features are ideal.

Soil Conditions: While specific soil preferences aren’t well-documented, most wetland plants appreciate rich, organic soils that stay consistently moist to saturated.

Climate Considerations: Based on its natural range from California to Wyoming, this species likely tolerates a wide range of temperature conditions, but always with that critical moisture component.

The Annual Challenge: Remember, this is an annual plant, so you’ll need to allow it to set seed for future generations or collect and replant seeds each year.

A Plant for the Patient Gardener

Smooth-Seed Pygmyweed isn’t for everyone, and that’s okay! It’s a specialized plant for specialized situations. If you’re working on wetland restoration, creating authentic native plant communities, or simply love the challenge of growing unusual natives, this tiny pygmyweed might just capture your heart.

The beauty of native gardening lies not just in the showstoppers, but in the quiet workers like Smooth-Seed Pygmyweed that help complete the ecological puzzle. Sometimes the smallest plants play the biggest roles in keeping our natural systems healthy and functioning.

So next time you’re planning a wetland garden or wondering what to do with that persistently soggy spot in your yard, consider giving this little native a chance. You might just discover that sometimes the most unassuming plants make the most rewarding gardening adventures.

Wetland Status

The rule of seasoned gardeners and landscapers is to choose the "right plant for the right place" matching plants to their ideal growing conditions, so they'll thrive with less work and fewer inputs. But the simplicity of this catchphrase conceals how tricky plant selection is. While tags list watering requirements, there's more to the story.

Knowing a plant's wetland status can simplify the process by revealing the interaction between plants, water, and soil. Surprisingly, many popular landscape plants are wetland species! And what may be a wetland plant in one area, in another it might thrive in drier conditions. Also, it helps you make smarter gardening choices and grow healthy plants with less care and feeding, saving you time, frustration, and money while producing an attractive garden with greater ecological benefits.

Regions
Status
Moisture Conditions

Arid West

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Atlantic and Gulf Coastal Plain

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Great Plains

FACW

Facultative Wetland - Plants with this status usually occurs in wetlands but may occur in non-wetlands

Western Mountains, Valleys, and Coast

FACW

Facultative Wetland - Plants with this status usually occurs in wetlands but may occur in non-wetlands

Smooth-seed 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 solieri (Gay) F. Meigen - Smooth-Seed Pygmyweed

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