Japanese Hop
Monologue ~Leaf Sound Notebook~
So this plant's name is Japanese hop.
I see it everywhere.
Or rather, I've cut down quite a lot of it.
Its ability to entwine itself around other plants is incredible.
Basic Information
Scientific name: Humulus japonicus (or Humulus scandens)
English name: Japanese Hop, Annual Hop
Cannabaceae family, Humulus genus (or Japanese hop genus), annual climbing herb
Origin: East Asia (Japan, China, Korean Peninsula)
A native species that grows wild throughout Japan
Morphological Characteristics
Plant height: Vines grow to 3-10m
Stem: Quadrangular, covered with downward-pointing prickles
Leaves: Opposite, palmately 5-7 lobed, with serrated margins
Leaf surface is rough, with glandular dots on the underside
Flowers: Dioecious
Male flowers: Panicles, pale yellow-green, with 5-lobed perianth and 5 stamens
Female flowers: Spikes, enclosed in bracts
Flowering period: August to October
Fruit: Achene, enclosed in bracts, forming a pinecone-like shape
Ecology and Distribution
Widely distributed from lowlands to mountainous areas throughout Japan
Grows on roadsides, in wastelands, along riverbanks, and at the edges of forests
Prefers sunny locations
Extremely high reproductive capacity; grows by covering other plants
Propagates by seeds, with a single plant producing tens of thousands of seeds
Clings to other plants and structures using the prickles on its stems
Uses and Culture
Traditionally, the fibers of the stems were used as material for cloth and rope
Young shoots were sometimes eaten as wild vegetables, but this is not common
Used as a crude drug (Rissou)
The related species, hop (Humulus lupulus), is famous as a beer ingredient, but Japanese hop cannot be used as a substitute because its bitterness is different
Regarding Edibility
While young shoots are considered edible, it is not recommended
The entire stems and leaves have fine prickles that irritate the skin when touched
It is not tasty due to its strong harshness and bitterness
If consumed, it must be thoroughly boiled to remove the harshness
It is generally not treated as an edible plant, and information regarding its safety as a food ingredient and preparation methods is limited
Points of Caution
The stems and leaves have sharp, downward-pointing prickles that hurt if touched with bare hands
People with sensitive skin may experience rashes
It has an extremely strong reproductive capacity and will cover other plants if left unchecked
A troublesome weed that entangles itself around crops and garden trees, causing damage.
Its pollen can sometimes cause allergies.
In some regions of North America and Europe, it is considered a problematic invasive species.
Extermination and Management Methods
Pulling it out by the roots while it is young is effective.
Because it has thorns, always wear thick gloves.
It is important to remove it before it produces seeds.
The use of herbicides may be considered to kill the underground parts as well.
If left unattended, it will spread further the following year, so continuous management is necessary.
Reference URLs
National Institute for Environmental Studies: Invasive Species Database
Plant Observation in Mikawa
Okayama University of Science: Plant Ecology Laboratory
NARO: Weed Illustrated Guide