Japanese Hops

Japanese Hops

Japanese hops grows rapidly and is capable of smothering native plants. It can form dense mats several feet deep that block light to the plants underneath, preventing new plants from emerging. Additionally, it can twine around understory trees and shrubs, which can cause them to break or fall over.

Common Name: Japanese hops

Scientific Name: Humulus japonicus

Native Range: Temperate Asia

Background

Japanese hops is a large, twining vine that was imported to the U.S. in the late 1800s for use as an Asian tonic and ornamental vine—it is still sold for these purposes. Japanese hops are less desirable for brewing beer than common hops (Humulus lupulus).

Habitat

Japanese hops prefers moist, well-lit areas and typically colonizes areas such as stream banks, floodplains, roadsides, and forest edges. Growth is less in sites that are shaded and/or dry.

NYS Distribution Map

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Identification

Japanese hops are herbaceous, annual, twining vines that can grow up to 35-feet long. The leaves have five to seven palmately (like a hand) arranged lobes with toothed edges. Both leaves and stems have hooked hairs present. The hooked hairs on the stem can be used to distinguish this species from look-a-likes and are characterized as sharp and downward pointing. Japanese hops flowers in mid-to-late summer with short flower spikes. The flowers are green with five petals.

Impact

Japanese hops grows rapidly and is capable of smothering native plants. It can form dense mats several feet deep that block light to the plants underneath, preventing new plants from emerging. Additionally, it can twine around understory trees and shrubs, which can cause them to break or fall over.