Botanical description: Someone introduced the Japanese hops vine to North America in the 19th century. The attractive foliage and fast rate of growth recommended this annual vine to gardeners, and the plant gained in popularity through the 40s. Humulus japonicus hopped the garden fence and has been self sowing on disturbed and forgotten sites since. Besides growing thirty-five feet in a single season, the vine also produces a prodigious amount of seed on female plants, which can be carried on wind or water, along the moist habitats it prefers. Unlike its close relative, Humulus lupulus, Japanese hops cannot be used in the production of beer, as it lacks the requisite oily resins that impart the distinctive flavor. It has maintained the genetic marker that covers stems and leaves with downward pointing prickles or ‘hooks’ that enable more efficient scrambling over other plants and make encounters dangerous for bare skin. While Humulus japonicus can smother other plants in a single season, it is an early colonizer of disturbed sites and edges that cannot tolerate shade, disappearing if sites transition into woodlands.