SafePlants

Japanese Alder (Alnus japonica)

The Japanese Alder, scientifically known as Alnus japonica, is a deciduous tree prized for its rapid growth and adaptability to wetland environments.

Considerations for Pets

• Japanese Alder is a deciduous tree.

Considerations for Children

• Japanese Alder is a deciduous tree.

Taxonomy and Nomenclature

• Scientific Name: Alnus japonica
• Common Name: Japanese Alder
• Family: Betulaceae (Birch Family)
• Genus: Alnus
• Synonyms: Alnus japonica (Thunb.) Steud.
• Group: Dicot

Distribution and Habitat

• Native to Taiwan, Japan, and Northeast Asia, including China and Korea (specifically Hamgyeongbuk-do).
• Widely distributed in wetlands in northern Japan.

Morphological Characteristics and Growth Habits

• Deciduous tree, growing up to 22 meters (approximately 72 feet) tall.
• Fast growth rate.
• Hardy to zone 4 (UK).
• Flowers bloom from February to March.
• The flowers are monoecious.
• Can be grown as Bonsai
• Shrub or tree with a dense crown, typically grows 3-10 meters tall, exceptionally to 20 meters.

Ecological Role

• Japanese alder forests are common in wetlands, but seedling establishment can be rare in mires.
• Seeds are dispersed widely, and seed density is high in alder forests compared to herbaceous fens.
• Japanese alder seeds can germinate under both herbaceous fen and alder forest conditions

Quirky Facts

• One Alnus maximowiczii (another type of Alder) can shed an estimated 4 million pollen.
• The Japanese name for Alnus japonica is Hannoki (&#27035&#12398&#26408).

Traditional and Medicinal Uses

• In natural medicine, Japanese Alder (Alnus japonica) has been used as a medicinal herb.
• Japanese Alder Flower Essence is believed to help strengthen confidence and quiet self-doubt.

Further Information

• RHS (Royal Horticultural Society) provides information on Alnus japonica.
• Dave's Garden is a community where gardeners share tips and ideas.