Goutweed, Pacific Northwest
Goutweed (ground elder) is a plant that is native to Europe and northern Asia. The early settlers brought it to North America as an ornamental garden plant and a ground cover. Today it is a problematic invasive species that is commonly found in moist forests, ravine systems and along water courses, l have seen it so thick along creeks that it has joined across the center to cover sections of the waterway completely.
It blooms between May and June, producing tiny white flowers arranged in flat topped clusters called compound umbels, which are held above the foliage on leafy stems looking quite a bit like Queen Anne’s Lace. It can reproduce by seed but needs disturbed dirt to sprout, but it can also rapidly expand by the spreading of its aggressive rhizomes. Goutweed forms thick patches that compete with native plants for water and light.
The reason plants like Goutweed can move so quickly over a huge area is because of humans dumping yard waste in the forest, yard waste that contains rhizomes of the plant.
Because it has limited success reproducing by seed, small patches of it can be easily destroyed/removed by digging up the plant making sure to remove all the rhizomes or covering with a tarp at least one growing season. Plants dug up with intact rhizomes should be dried in the sun for several days to kill them. Do not compost Goutweed plants or their rhizomes.