North America Non-native Plant

Bellard’s Smartweed

Botanical name: Polygonum patulum

USDA symbol: POPA9

Life cycle: annual

Habit: forb

Native status: Non-native, reproduces and persists in the wild in the lower 48 states  

Synonyms: Polygonum bellardii auct. non All. (POBE8)   

Bellard’s Smartweed: An Uninvited Garden Guest You Probably Don’t Want If you’ve stumbled across the name Bellard’s smartweed (Polygonum patulum) in your gardening research, you might be wondering whether this little annual deserves a spot in your landscape. The short answer? Probably not. But let’s dive into why this European ...

Bellard’s Smartweed: An Uninvited Garden Guest You Probably Don’t Want

If you’ve stumbled across the name Bellard’s smartweed (Polygonum patulum) in your gardening research, you might be wondering whether this little annual deserves a spot in your landscape. The short answer? Probably not. But let’s dive into why this European import has made itself at home across parts of the United States and what you should know about it.

What Is Bellard’s Smartweed?

Bellard’s smartweed is a small annual forb—essentially a non-woody herbaceous plant that completes its entire life cycle in one growing season. Originally from Europe and the Mediterranean region, this plant has established itself in Alabama, California, and Delaware, though it may be present in other states as well.

You might also see this plant listed under the synonym Polygonum bellardii in some older references, but don’t let the name confusion fool you—it’s the same unremarkable little plant.

Why You Probably Don’t Want It

Here’s the thing about Bellard’s smartweed: it’s not exactly what you’d call garden-worthy. This introduced species tends to pop up in disturbed areas and doesn’t offer much in the way of ornamental value. Its flowers are tiny and inconspicuous, and the plant itself has a rather weedy appearance that most gardeners would prefer to avoid.

While it’s not currently listed as invasive or noxious, it’s also not contributing much to local ecosystems. As a non-native species, it doesn’t provide the same benefits to native wildlife and pollinators that indigenous plants offer.

Growing Habits and Characteristics

If you do encounter Bellard’s smartweed (likely uninvited), here’s what you can expect:

  • Annual growth habit—dies back each year
  • Forb classification with no woody stems
  • Adaptable to various moisture conditions
  • Variable wetland preferences depending on region

Wetland Tolerance Across Regions

One interesting characteristic of this plant is how its water preferences change depending on where it’s growing. In some regions like the Great Plains and Arid West, it tends to favor wetter areas, while in the Midwest, it almost never appears in wetlands. This adaptability is part of what has helped it establish in different parts of the country.

Better Native Alternatives

Instead of letting Bellard’s smartweed take up residence in your garden, consider these native alternatives that will provide actual benefits to your local ecosystem:

  • Native smartweed species (Persicaria species) that support local wildlife
  • Regional wildflowers that attract pollinators
  • Indigenous forbs suitable for your specific growing conditions

The Bottom Line

While Bellard’s smartweed isn’t going to take over your entire landscape, it’s also not going to enhance it. This little European immigrant is more of a background player—one that’s better left in the wild rather than welcomed into carefully planned garden spaces.

If you’re looking to create a thriving, ecologically beneficial garden, your time and energy are better spent on native species that will support local wildlife, attract pollinators, and contribute to the health of your regional ecosystem. Save the garden real estate for plants that truly deserve it!

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

FACW

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

Atlantic and Gulf Coastal Plain

FAC

Facultative - Plants with this status can occur in wetlands and non-wetlands

Eastern Mountains and Piedmont

FAC

Facultative - Plants with this status can occur in wetlands and non-wetlands

Great Plains

FACW

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

Midwest

UPL

Obligate Upland - Plants with this status almost never occurs in wetlands

Northcentral & Northeast

FACU

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

Western Mountains, Valleys, and Coast

FACW

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

Bellard’s Smartweed

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Caryophyllidae

Order

Polygonales

Family

Polygonaceae Juss. - Buckwheat family

Genus

Polygonum L. - knotweed

Species

Polygonum patulum M. Bieb. - Bellard's smartweed

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