North America Native Plant

Striped Knotweed

Botanical name: Polygonum striatulum

USDA symbol: POST7

Life cycle: annual

Habit: subshrub

Native status: Native to the lower 48 states  

Synonyms: Polygonum brasiliense K. Koch (POBR20)  âš˜  Polygonum braziliense K. Koch, orth. var. (POBR3)  âš˜  Polygonum camporum Meisn. (POCA28)  âš˜  Polygonum texense M.C. Johnst. (POTE6)   

Striped Knotweed: A Humble Native with Hidden Garden Potential Meet striped knotweed (Polygonum striatulum), one of those quiet native plants that doesn’t demand attention but quietly does its job in the ecosystem. While it may not win any beauty contests, this unassuming member of the buckwheat family has earned its ...

Striped Knotweed: A Humble Native with Hidden Garden Potential

Meet striped knotweed (Polygonum striatulum), one of those quiet native plants that doesn’t demand attention but quietly does its job in the ecosystem. While it may not win any beauty contests, this unassuming member of the buckwheat family has earned its place in the native plant world of the south-central United States.

What Exactly Is Striped Knotweed?

Striped knotweed is a native forb that can behave as either an annual or perennial, depending on growing conditions. As a member of the herb family, it lacks woody stems and keeps its growing points at or near ground level. Don’t let its modest appearance fool you – this little plant has been holding down the fort in American landscapes long before European settlers arrived.

Where You’ll Find This Native Gem

This hardy little plant calls the south-central United States home, with confirmed populations in Louisiana, Nebraska, Oklahoma, and Texas. It’s a true red, white, and blue native that has adapted to the diverse conditions found across these states, from the humid Gulf Coast to the drier Great Plains.

The Wetland Connection

Here’s where striped knotweed gets interesting from an ecological standpoint. It’s classified as a facultative wetland plant across its range, meaning it usually hangs out in wetlands but isn’t picky enough to turn down a nice upland spot. This flexibility makes it a valuable player in transitional zones where wet and dry conditions meet.

Should You Plant Striped Knotweed in Your Garden?

Let’s be honest – striped knotweed isn’t going to be the star of your garden show. It’s more of a supporting cast member that works behind the scenes. Here’s when you might consider adding it to your landscape:

  • You’re creating a native plant garden focused on local species
  • You have wet areas or seasonal flooding that need stabilization
  • You want to support local ecosystems with truly native plants
  • You appreciate the subtle beauty of plants that don’t need constant attention

However, if you’re looking for showy flowers, dramatic foliage, or a real garden focal point, you might want to pair this with more visually striking native companions.

Growing Striped Knotweed Successfully

The good news about growing striped knotweed is that it’s likely as low-maintenance as they come – after all, it’s been thriving without human help for centuries. Based on its native range, it should be hardy in USDA zones 6 through 9.

Planting and Care Tips

  • Location: Can handle both wet and moderately dry conditions, making it perfect for problem spots in your yard
  • Soil: Not particularly fussy about soil type
  • Watering: Once established, should handle natural rainfall in its native range
  • Maintenance: Likely requires minimal care – let it do its thing naturally

The Wildlife Factor

While specific wildlife benefits for striped knotweed aren’t well-documented, plants in the knotweed family generally provide seeds for birds and nectar for small pollinators. As a native plant, it’s almost certainly supporting local wildlife in ways we’re still discovering.

The Bottom Line

Striped knotweed might not be the most glamorous choice for your garden, but it represents something valuable – a connection to the native plant communities that have sustained local wildlife for generations. If you’re passionate about creating authentic native habitat or need a tough plant for challenging wet areas, striped knotweed deserves consideration.

Just remember that finding this plant at your local nursery might be a challenge, as it’s not commonly cultivated. You might need to seek out specialty native plant sources or consider collecting seeds responsibly from wild populations where permitted.

Sometimes the most meaningful garden choices aren’t about creating the most Instagram-worthy landscape – they’re about creating spaces where native plants and wildlife can thrive together, just as they have for countless generations.

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

FACW

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

Great Plains

FACW

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

Striped Knotweed

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 striatulum B.L. Rob. - striped knotweed

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