Vaccinium hirtum

Flower name
Vaccinium hirtum
Scientific name
Vaccinium hirtum
Alias臼の木, Usunoki tree, カクミノスノキ, アカモジ
Place of originJapan
Place of floweringLow mountains
Flowering seasonApril, May, June

What is Vaccinium hirtum

Usunoki (Usunoki tree, Japanese name: 臼の木, Scientific name: Vaccinium hirtum)
Usunoki is a deciduous shrub in the genus Vaccinium of the family Ericaceae.
It is also known by other names such as Kakumino-sunoki (“angular-fruited vinegar tree”), Akamoji, and Usunoki tree.

It grows naturally on sunny forest edges and rocky areas in mountainous regions from Hokkaido to Kyushu in Japan.

The plant grows 50–100 cm tall, with smooth gray-brown bark.
Leaves are ovate with an acute apex and fine serrations along the edges, arranged alternately. New leaves are red, turn green, and then change color again in autumn.
From April to June, bell-shaped flowers bloom from the axils of leaves on branches grown in the previous year.
From July to September, red berries (fleshy fruits) are formed. The fruit is round but angular, with a mortar-shaped depression at the tip.

Origin of the name “Usunoki”
The Japanese name “Usunoki” comes from the mortar-like depression at the tip of the fruit.
However, actual mortars are made from larger, harder, and more durable woods such as zelkova (Keyaki) or Mejiro-kaba.

Flower Language
“Reserve,” “Modesty,” “Neatness”

Related Species in the Genus Vaccinium
Akushiba (Vaccinium japonicum)
Usunoki (Vaccinium hirtum)
Kuromamenoki (Vaccinium uliginosum)
Shashambo (Vaccinium bracteatum)
Sunoki (Vaccinium smallii var. glabrum) (black fruits)
Natsuhaze (Vaccinium oldhamii) (ripens to black)
Blueberry
General Information
Common name: Usunoki
Scientific name: Vaccinium hirtum
Synonyms: Kakumino-sunoki, Akamoji, Usunoki tree
Chinese name: 日本越橘, 红果越桔
Classification: Plantae, Angiosperms, Eudicots, Ericales, Ericaceae, Vaccinium, hirtum
Distribution: Mountain areas from Hokkaido to Kyushu
Habitat: Sunny forest edges, rocky areas
Life form: Deciduous shrub, fruit-bearing plant
Height: 50–100 cm
Bark: Smooth, gray-brown
Petiole: 0.1 cm
Leaf texture: Hair on the underside and main vein
Leaf shape: Ovate with an acute apex
Leaf color: Red (young) → Green → Red in autumn
Leaf length: 2–4 cm
Leaf width: 1–2 cm
Leaf margin: Fine serrations
Leaf arrangement: Alternate
Flower stalk length: 0.5 cm
Blooming period: April–June
Flower location: Leaf axils of previous year’s branches
Corolla shape: Bell-shaped
Flower diameter: 0.6–0.7 cm
Flower color: Yellow-green with pale red vertical stripes
Flowers per cluster: 2–3
Flower orientation: Downward
Pistil: 1
Stamens: 10
Fruiting period: July–September
Fruit type: Berry (fleshy fruit)
Fruit diameter: 0.8 cm
Fruit color: Red
Fruit shape: Angular spherical with a mortar-like indentation at the tip
Edibility: Tart and edible, but small and not sweet
Uses: Ornamental tree, fruit-bearing plant