Iva axillaris Pursh. Long-lived perennial with vigorous creeping roots , to 0.6 m tall. Poverty sumpweed is a widespread native of Western North America and a desirable component of salt marsh and alkali plains communities. However, it sometimes forms large clonal colonies on sites subjected to disturbances such as cultivation or overgrazing. Once established, colonies are difficult to eradicate.
Studies suggest that plants have allelopathic properties.
Colonies in cultivated fields can significantly reduce crop yields. Handling foliage may cause contact dermatitis and inhaling pollen can trigger allergic responses in sensitive individuals. Elsewhere it has been associated with selenium poisoning of livestock grazing on high selenium soils, but animals seldom consume the unpalatable foliage. No information available. Margins smooth .