North America Native Plant

Kellogg’s Knotweed

Botanical name: Polygonum polygaloides kelloggii

USDA symbol: POPOK

Life cycle: annual

Habit: forb

Native status: Native to Canada âš˜ Native to the lower 48 states  

Synonyms: Polygonum kelloggii Greene (POKE2)  âš˜  Polygonum unifolium Greene (POUN5)   

Kellogg’s Knotweed: A Lesser-Known Native Annual for Western Gardens If you’re looking to expand your native plant palette beyond the usual suspects, you might want to get acquainted with Kellogg’s knotweed (Polygonum polygaloides kelloggii). This unassuming annual forb might not win any flashy flower contests, but it has some interesting ...

Kellogg’s Knotweed: A Lesser-Known Native Annual for Western Gardens

If you’re looking to expand your native plant palette beyond the usual suspects, you might want to get acquainted with Kellogg’s knotweed (Polygonum polygaloides kelloggii). This unassuming annual forb might not win any flashy flower contests, but it has some interesting qualities that make it worth considering for certain garden situations.

What is Kellogg’s Knotweed?

Kellogg’s knotweed is a native annual forb that belongs to the buckwheat family. As a forb, it’s an herbaceous plant without woody stems – think of it as the botanical equivalent of a soft-spoken neighbor who quietly goes about their business without making a fuss. You might also see this plant listed under its synonyms Polygonum kelloggii or Polygonum unifolium in older references.

Where Does It Call Home?

This native beauty has quite an impressive range across western North America. You’ll find Kellogg’s knotweed naturally occurring from British Columbia down through much of the American West, including Arizona, California, Colorado, Idaho, Montana, Nevada, Oregon, Utah, Washington, and Wyoming. It’s truly a child of both Canada and the lower 48 states.

The Wetland Connection

Here’s where things get interesting: Kellogg’s knotweed has a thing for moisture. Across its range – whether in the Arid West, Great Plains, or Western Mountains regions – it’s classified as a Facultative Wetland plant. This means it usually hangs out in wetlands but isn’t completely married to them. Think of it as a plant that prefers its feet damp but won’t throw a tantrum if things dry out occasionally.

Should You Grow It?

The honest answer is: it depends on what you’re trying to achieve. Here are some considerations:

Reasons You Might Want to Try It:

  • It’s genuinely native to a huge swath of western North America
  • Perfect for naturalized areas or native plant restoration projects
  • Great for those tricky spots that stay a bit soggy
  • As an annual, it won’t overstay its welcome if you change your mind
  • Supports the goal of using locally native species

Reasons You Might Want to Pass:

  • Limited information available about its garden performance and aesthetics
  • May not provide the showy display that many gardeners seek
  • Being an annual, you’ll need to replant or rely on self-seeding each year

Growing Kellogg’s Knotweed

Unfortunately, detailed growing information for this specific plant is quite limited in available resources. However, based on its wetland status and native habitat, here’s what we can reasonably infer:

  • Provide consistent moisture, especially during the growing season
  • It likely tolerates a range of soil types, given its wide geographic distribution
  • Being native to diverse elevations and climates, it’s probably fairly adaptable
  • As an annual, focus on providing good conditions for seed germination and establishment

A Word of Caution

Here’s the thing about lesser-known native plants: sometimes they’re lesser-known for a reason. While Kellogg’s knotweed isn’t listed as invasive or noxious, the limited cultivation information means you’d be somewhat pioneering if you choose to grow it. Consider starting small and observing how it behaves in your specific garden conditions.

The Bottom Line

Kellogg’s knotweed represents one of those intriguing native plants that might be perfect for very specific situations – particularly if you’re working on wetland restoration, creating naturalized areas, or simply want to support truly local flora. While it may not be the star of your flower border, it could play a valuable supporting role in the right garden setting.

If you’re curious about this plant, try contacting local native plant societies or botanical gardens in its range – they might have more hands-on experience with growing it successfully. Sometimes the best gardening adventures come from exploring the plants that don’t have lengthy care guides written about them yet.

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

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

Kellogg’s 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 polygaloides Wall. ex Meisn. - milkwort knotweed

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