Also known as creeping Jenny and creeping loosestrife, moneywort is a vigorous, prostrate, evergreen perennial in the primrose family, Primulaceae, that also includes shooting star, cyclamen, and scarlet pimpernel. It is native to Europe and western Asia but was introduced into the US in the 1700s as a groundcover and now grows from Minnesota south to Louisiana, east to Georgia, north to Maine, and in Nebraska, Kansas, Colorado, and parts of Washington, Oregon, and California. Plants prefer damp to wet areas and tolerate full sun to full shade. They are found in floodplain forests and woodlands, along riverbanks and shorelines of lakes and ponds, in wet meadows, bogs, marshes, swamps, grasslands, and disturbed areas including cultivated or fallow fields, lawns, roadsides, railroad tracks, and ditches. Although useful as a groundcover, moneywort can become aggressive in favorable conditions and is considered an invasive species in some areas.
Description: Moneywort has slender creeping stems that form slender fibrous roots when the nodes touch the ground. The stems can grow over three feet long and two to four inches tall and branch oten to form dense mats. The round to oval leaves are opposite, up to 1.5 inches long, occur in pairs on short leaf stems, and have red to black glandular dots on their upper surface. Many plants do not flower but when flowers do appear they have a yellow 5-lobed corolla with orange to black dots, are produced singly in the leaf exils from mid- to late summer, and give way to small round capsules containing many seeds. Plants spread by seed and rooting stems.
Control: The slender root system allows the plant to be easily pulled up but beware because any stem left behind is likely to give rise to a new plant. Covering a mowed patch of moneywort for a growing season with a dense mulch such as newspaper or cardboard is effective. In severe cases glyphosate can be employed but will damage all vegetation that it contacts.