Ask the Expert: What is the name of this flowering plant?

Knotweed

Hi,

This plant was about 1″ tall this May and I thought it was Oleander. Now 3 months later it is more than 3feet tall and started growing multiple buds off of a single stalk. What is the name of this plant? Niru

Plant Expert Reply:

I believe the plant is a Persicaria lapathifolium commonly known as a knotweed or in this case a pale smartweed.  Although some states consider it a weed, in Illinois it is considered a native wildflower. It likes marshy or boggy types areas.  It will attract bees, wasps, flies and small butterflies.  This plant contributes to the habitat for wetland areas by giving several caterpillar species a food source. These caterpillars become the food source for many types of wildlife including waterfowl.

Keep in mind this plant can become weedy and very invasive.