Non-native Plants

Willdenow’s Spikemoss

Selaginella willdenowii

USDA symbol: SEWI

perennial vine

Lower 48 states: non-native, naturalized
Puerto Rico: non-native, naturalized

Meet Willdenow’s spikemoss (Selaginella willdenowii), a fascinating little plant that’s been fooling people with its name for ages. Despite what its common name suggests, this isn’t a moss at all – it’s actually a lycophyte, an ancient group of plants that’s been around since before dinosaurs roamed the Earth. Pretty ...

Willdenow’s Spikemoss: The Ancient Ground Cover That’s Not Actually Moss

Meet Willdenow’s spikemoss (Selaginella willdenowii), a fascinating little plant that’s been fooling people with its name for ages. Despite what its common name suggests, this isn’t a moss at all – it’s actually a lycophyte, an ancient group of plants that’s been around since before dinosaurs roamed the Earth. Pretty cool, right?

What Exactly Is Willdenow’s Spikemoss?

This perennial plant is what botanists call a living fossil. As a member of the lycophyte family, it’s more closely related to ferns than to true mosses. Willdenow’s spikemoss grows as a low, creeping herb that forms dense, carpet-like mats. It’s covered in tiny, scale-like leaves that give it a delicate, almost prehistoric appearance.

The plant typically stays quite small, reaching only 2-6 inches in height, but it can spread horizontally to create substantial ground coverage. Its intricate, branching pattern and fine texture make it look like nature’s own living tapestry.

Where You’ll Find It

Originally from tropical regions of Asia, Willdenow’s spikemoss has made itself at home in warmer parts of the United States. You can currently find it growing wild in Florida and Puerto Rico, where it has established itself as a non-native species that reproduces successfully without human intervention.

  • Species observed
  • No observations

In terms of habitat preferences, this little plant is quite adaptable. In the Atlantic and Gulf Coastal Plain regions, it can handle both wetland and non-wetland conditions (what scientists call facultative). In the Caribbean, it leans toward drier upland areas but can still tolerate some moisture.

Is It Beneficial in the Garden?

Willdenow’s spikemoss can offer several benefits to the right garden setting:

  • Excellent ground cover: Its mat-forming habit makes it useful for covering bare soil
  • Erosion control: The dense growth can help stabilize soil on slopes
  • Unique texture: Adds an unusual, fine-textured element to plant compositions
  • Low maintenance: Once established, it generally takes care of itself
  • Conversation starter: Its ancient lineage makes it a fascinating talking point

However, since it’s not native to most areas where it’s found, you might want to consider native alternatives that provide similar benefits while supporting local ecosystems. Native mosses, sedges, or other low-growing native plants could offer comparable ground cover functions.

How to Identify Willdenow’s Spikemoss

Spotting this plant in the wild (or in a garden) is all about knowing what to look for:

  • Size: Very low-growing, rarely exceeding 6 inches tall
  • Growth pattern: Spreads horizontally in dense mats
  • Leaves: Tiny, scale-like leaves arranged in overlapping patterns
  • Branching: Intricate, repeatedly branching stems
  • Color: Typically bright to dark green
  • Texture: Fine, delicate appearance that’s soft to the touch

The easiest way to distinguish it from true moss is by its more complex branching pattern and the way its leaves are arranged in neat, overlapping scales rather than the simpler leaf structures you’d see on actual moss.

Growing Conditions

If you’re in USDA hardiness zones 9-11 and considering adding this plant to your landscape, it thrives in:

  • Humid, shaded to partially shaded locations
  • Consistently moist (but not waterlogged) soil
  • Areas with good air circulation
  • Protected spots away from harsh winds

Keep in mind that as a non-native species, it’s worth considering whether native alternatives might better serve your garden’s ecological goals. Many native ground covers can provide similar aesthetic and functional benefits while supporting local wildlife and maintaining regional biodiversity.

The Bottom Line

Willdenow’s spikemoss is undeniably fascinating – a living link to Earth’s ancient past that can add unique character to the right garden setting. While it’s not harmful to grow where it’s already established, thoughtful gardeners might want to explore native options first. Either way, if you encounter this little moss that’s not a moss, take a moment to appreciate its incredible evolutionary journey. After all, it’s been perfecting its ground-hugging lifestyle for hundreds of millions of years!

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 care and fewer inputs. But the simplicity of this catchphrase conceals how tricky plant selection can be if you don't have the right information. While tags on nursery plants 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. You might be surprised to learn that popular landscape plants are wetland species! And what may be a wetland plant in one area, in another it might thrive in drier conditions. The table below gives insight into the preferred growing conditions of this plant throughout its geographical distribution.

Region
Preferred Habitat

Atlantic and Gulf Coastal Plain (AL, AR, DC, DE, FL, GA, IL, KY, LA, MD, MS, MO, NC, NJ, OK, PA, SC, TN, TX, VA)

Facultative

Caribbean (PR, VI)

Facultative Upland
Wetland Glossary
Obligate Wetland
Facultative Wetland
Facultative
Facultative Upland
Obligate Upland
Almost always occurs in wetlands
Usually occurs in wetlands but may occur in non-wetlands
Can occur in wetlands and non-wetlands
Usually occurs in non-wetlands but may occur in wetlands
Almost never occurs in wetlands

Classification

Group: Lycopod
Kingdom: Plantae - Plants
Subkingdom: Tracheobionta - Vascular plants
Superdivision: N/A
Division: Lycopodiophyta - Lycopods
Subdivision: N/A
Class: Lycopodiopsida
Subclass: N/A
Order: Selaginellales
Family: Selaginellaceae Willk. - Spike-moss family
Genus: Selaginella P. Beauv. - spikemoss

Species: Selaginella willdenowii (Desv. ex Poir.) Baker - Willdenow's spikemoss

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