Mugwort
Artemisia Vulgaris (USDA, Wikipedia, GoBotany, IPANE, a.k.a. Common Wormwood ) is an invasive weed, which establishes a root network to spread itself. It spreads rapidly in disturbed areas. It is found throughout the world, and does have medicinal properties!
It is identified by its leaf, which has many fronds, and a pale underside.
Removal
Mugwort can be pulled by hand. It spreads by rhizome, so when pulling it, attention should be paid to extracting the spreading rhizomes from the ground.
Cutting Mugwort doesn't seem to hurt it.
Common Mis-identificatlons
Common, or Annual Ragweed (Ambrosia Artemisiifolia, Wikipedia, USDA, GoBotany) is a native plant frequently found in places with Mugwort, and the leaves are confusingly similar (which is supposedly why the species name plays off of Artemisia, the Mugwort family). The Ragweed leaf outline is triangular, whereas Mugwort has is narrower at the base.