This is one of those plants with a dual personality. On the one hand, goutweed (Aegopodium podograria), especially the variegated type, is often used as an ornamental groundcover. Unfortunately, the trait that makes it such a good groundcover also can allow it to become an invasive weed. It spreads like crazy! Also known as Bishop's Weed or Snow on the Mountain, this perennial spreads by rhizomes.

The most common form is the variegated one that people grow as an ornamental. However, the straight green species form is even more aggressive because it contains more chlorophyll.

Since this perennial plant is usually growing mixed in with your other perennial plants, it can be very difficult to remove. Digging or grubbing it out in the spring will give temporary relieve but even a small part of the rhizome left in the ground will regenerate a new plant. Therefore, by autumn, most of the mess will be back and the following spring, you will need to do it all over again.

Actual removal will probably require removing all the desirable perennials and then treating the goutweed with an herbicide such as glyphosate. Even then, you may need to repeat applications whenever new goutweed raises its ugly (or pretty) head.

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.