Humulus japonicus Siebold & Zucc.
Japanese hops
Japanese hops is native to temperate regions of eastern Asia—China, Japan, Korea, Taiwan and the Russian Federation—as well as to tropical Vietnam. It was probably imported for cultivation, but it escaped and spread quickly. It is related to the variety of hops, Humulus lupulus, used for flavoring and preserving beer, and may be used as a less suitable substitute for this purpose. Japanese hops is considered an invasive in Connecticut, Delaware, Indiana, Maryland, Pennsylvania, Virginia, and the District of Columbia.
Plants: A fast-growing vine with tiny hooks on its stems and leaves that allow it purchase on nearly anything it encounters, reaching between 3–20′ (91–609 cm) in length. If you want to get technical, Japanese hops are bines, not vines: they climb with little hooks rather than wrapping tendrils around things like grapes, or using suckers like ivy. Stems are green or reddish purple, with ridges running along the length of the stem.
Leaves: rough, with short hairs and 5-9 palmate lobes, and are 2–6″ (5–15 cm) in size, with long petioles (stems).
Flowers: Plants are dioecious. Male plants have large cone-shaped panicles up to 10″ (25 cm) long and 5″ (12 cm) wide; female flowers are about 1″ (2.5 cm) long. Though the panicles are large, the flowers are pale and unremarkable, each about ⅛″ (3.2 mm) in size. They appear early to mid-summer.
Fruits: Pendulous, green, conelike, ovoid to oblong, ½–1″ (1.5–3 cm).
Habitats: Anthropogenic (man-made or disturbed habitats), meadows and fields.
Online References:
References:
Humulus scandens auct. non (Lour.) Merr.
7/20/2013 · Wooden Bridge, East Pepperell, Massachusetts · ≈ 11 × 7″ (28 × 18 cm) 
Male flowers. · 7/20/2013 · Wooden Bridge, East Pepperell, Massachusetts · ≈ 5 × 6″ (13 × 14 cm) 
9/1/2013 · Trail Near James River, Midlothian, Virginia · ≈ 5 × 8″ (13 × 19 cm) 
7/20/2013 · Wooden Bridge, East Pepperell, Massachusetts · ≈ 7 × 10″ (16 × 25 cm) 
7/20/2013 · Wooden Bridge, East Pepperell, Massachusetts · ≈ 9 × 6″ (23 × 16 cm) 
Male flowers. · 7/20/2013 · Wooden Bridge, East Pepperell, Massachusetts · ≈ 6 × 8″ (14 × 20 cm) 
9/1/2013 · Trail Near James River, Midlothian, Virginia · ≈ 7 × 11″ (18 × 28 cm) 
7/12/2013 · Wooden Bridge, East Pepperell, Massachusetts · ≈ 2 × 1′ (59 × 39 cm) 
9/1/2013 · Trail Near James River, Midlothian, Virginia · ≈ 15 × 10″ (37 × 25 cm) 
Male flowers. · 7/20/2013 · Wooden Bridge, East Pepperell, Massachusetts · ≈ 5 × 8″ (12 × 19 cm) 
| Kingdom | Plantae | Plants, but not fungi, lichens, or algae (from Stearn's Botanical Latin) |
| Subkingdom | Tracheobionta | Vascular plants—plants with a “circulatory system” for delivering water and nutrients |
| Division | Magnoliophyta | Flowering plants, also known as angiosperms |
| Class | Magnoliopsida | Dicotyledons—plants with two initial seed leaves |
| Subclass | Rosidae | Roses, legumes, proteas, dogwoods, hydrangeas, mistletoes, euphorbias, grapes, many more |
| Order | Urticales | Includes cannabis, nettles, mulberries, elms, others |
| Family | Cannabaceae | A small but varied group whose best known members are marijuana and hops for beer |
| Genus | Humulus | Vines that climb with hooked hairs; Latin Humulus may mean “hop” |
| Species | japonicus | “From Japan” |
Humulus japonicus description by Thomas H. Kent, not updated.
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