Yellow Flag
Iris pseudacorus)

Yellow flag is native to Europe, Great Britain, North Africa and the Mediterranean region.  It is a popular ornamental plant for wet areas;  it escaped from cultivation and is found in marshes throughout the United States and Canada.  Many states list it as an invasive species because it can crowd out native pond plants.  It is planted in the gardens behind the Center where it is carefully monitored and controlled.

The roots of yellow flag are used in folk medicine to treat several ailments, but all parts of the plant can also cause vomiting and diarrhea.  Flowers are used to make a yellow dye and the roots produce a dark brown dye.

(Photo credits: Washington Noxious Weed Control Bureau)