Broadleaf Weed – Smartweed

(Polygonum pensylvanicum)

Smartweed – also referred to as Persicaria pensylvanica, Swamp Persicary, Glandular Persicary, Purple Head, Pinkweed and Hearts-ease – is a summer annual broadleaf weed. Polygonum pensylvanicum occurs in moist and wet locations, preferring disturbed sites such as waste ground and along roadsides and railroads. Smartweed can be found in most of the continental United States.

Identifying Smartweed -

Smartweed (or Pinkweed) can be identified as an vertical or ascending multi-branched summer annual. Its stems are branched, green or red in color and are swollen and jointed at the nodes. The leaves are smooth with sparse hairs and are sometimes marked with a purple blotch. A membranous sheath is present at the base of the petiole. Smartweed features fibrous roots branching from a shallow taproot.

In bloom, Smartweed features small white to pinkish colored flowers that grow singly on short stems, forming in clusters and branching from a common stem.

Smartweed Control -

Proper cultural practices, such as proper mowing and watering, can help to prevent Smartweed by creating dense turf, which inhibits the weed’s ability to grow. Physical removal (i.e. “weed pulling”) can be effective, although you will run the risk of spreading the seeds to additional areas of your lawn and landscaping.


Scotts LawnService uses a selective systemic weed control program to fight Smartweed in your lawn, which ensures the herbicide is moved throughout the weed, killing it completely root and all.

Scotts LawnService is the trusted industry leader for professional quality lawn care. Our exclusive lawn care products include premium grass seeds and professional-grade fertilizers; our lawn service teams consist of highly trained, industry-certified professionals. Contact a representative today for Smartweed control options available in your area and to learn how you can enjoy a lush, thicker lawn that only Scotts LawnService can deliver.