North America Native Plant

American Pillwort

Botanical name: Pilularia americana

USDA symbol: PIAM

Life cycle: perennial

Habit: forb

Native status: Native to the lower 48 states  

American Pillwort: A Unique Native Aquatic Fern for Specialized Gardens Meet American pillwort (Pilularia americana), one of North America’s most unusual native ferns. This quirky little plant might not win any beauty contests with flashy flowers, but it has its own subtle charm and plays an important ecological role in ...

American Pillwort: A Unique Native Aquatic Fern for Specialized Gardens

Meet American pillwort (Pilularia americana), one of North America’s most unusual native ferns. This quirky little plant might not win any beauty contests with flashy flowers, but it has its own subtle charm and plays an important ecological role in wetland environments across the continent.

What Makes American Pillwort Special?

American pillwort is a perennial forb that’s actually a fern in disguise. Instead of the typical frilly fronds we associate with ferns, this plant produces thin, grass-like leaves called phyllodia that emerge from creeping underground stems (rhizomes). It’s like nature’s version of a minimalist design – simple, clean lines with no fuss.

As a native species to the lower 48 states, American pillwort has been quietly doing its thing in wetlands long before European settlers arrived. It’s found naturally in Alabama, Arkansas, California, Georgia, Kansas, Missouri, Nebraska, Oklahoma, Oregon, South Carolina, Tennessee, Texas, and Washington – quite an impressive range for such a specialized plant!

Where Does American Pillwort Belong in Your Garden?

Here’s the thing about American pillwort – it’s not your average garden plant. This little fern is an obligate wetland species, which means it almost always occurs in wetlands across all regions of the country. If you’re dreaming of adding it to your regular flower border, you might want to think again.

American pillwort shines in:

  • Water gardens and pond margins
  • Bog gardens
  • Rain gardens
  • Naturalized wetland areas
  • Constructed wetlands for stormwater management

Growing Conditions and Care

If you’re intrigued by this unique native and have the right conditions, American pillwort can be a fascinating addition to specialized water features. Here’s what it needs to thrive:

Water Requirements: This plant lives for moisture. It needs consistently wet soil or can even grow in shallow standing water. Think pond edges, not rain-dependent garden beds.

Light Conditions: American pillwort adapts well to full sun or partial shade, making it flexible for various wetland garden designs.

Hardiness: Generally hardy in USDA zones 6-10, though this can vary depending on your specific region and local growing conditions.

Planting and Maintenance Tips

Once you’ve got the right soggy conditions, American pillwort is refreshingly low-maintenance:

  • Plant in wet soil or shallow water areas
  • Allow space for the plant to spread via its creeping rhizomes
  • Minimal fertilization needed – wetland plants are adapted to nutrient-poor conditions
  • Little to no pruning required
  • Watch for natural spreading, which can be beneficial for erosion control

Wildlife and Ecological Benefits

While American pillwort won’t attract butterflies like a native wildflower would (it doesn’t produce flowers), it still provides valuable ecological services. As part of wetland communities, it helps with water filtration, erosion control, and provides habitat structure for small aquatic creatures and amphibians.

Is American Pillwort Right for Your Garden?

Let’s be honest – American pillwort isn’t for everyone. If you’re looking for colorful blooms or a plant for your typical garden bed, this isn’t your match. But if you have a water feature, are creating a rain garden, or working on a naturalized wetland area, this native fern could be exactly what you need.

The real question is whether you have the right growing conditions. American pillwort’s obligate wetland status means it’s not going to compromise on its water needs. But for gardeners with the right wet spots, it offers the satisfaction of growing a truly native species that’s perfectly adapted to North American wetlands.

Consider American pillwort if you want to add authentic native character to your water garden or if you’re passionate about supporting indigenous plant communities. Just make sure you’ve got those wet feet ready – this little fern takes its moisture seriously!

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

Eastern Mountains and Piedmont

OBL

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

Great Plains

OBL

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

Midwest

OBL

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

Western Mountains, Valleys, and Coast

OBL

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

American Pillwort

Classification

Group

Fern

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision
Division

Pteridophyta - Ferns

Subdivision
Class

Filicopsida

Subclass
Order

Hydropteridales

Family

Marsileaceae Mirb. - Water-clover family

Genus

Pilularia L. - pillwort

Species

Pilularia americana A. Braun - American pillwort

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