Geum japonicum aka Asian Herb Bennet
Taxonomy ID: 22037
Geum japonicum, commonly known as Japanese avens or Asian herb bennet (Japanese: ダイコンソウ daikonsō; Korean: 뱀무 baem mu; Chinese: 日本路边青), is a herbaceous perennial in the rose family (Rosaceae). The species was described by Thunberg in 1784 and is placed within the subfamily Rosoideae and tribe Colurieae, alongside close relatives such as Potentilla and Fragaria. Plants grow from a basal rosette of leaves and reach approximately 0.6 m (2 ft) in height, producing yellow flowers on wiry stalks during early to mid-summer. The genus Geum as a whole comprises around 50 rhizomatous perennials, and members tend to remain evergreen except where winter temperatures fall below about −18 °C (0 °F).
The native range of Geum japonicum stretches across temperate East Asia, including Japan, Korea, Taiwan, much of China (North-Central, South-Central, Southeast and Xinjiang regions), and the Russian Far East (Kuril Islands). In Japan it grows in woods and thickets in hilly and low-mountain country and has been documented from regions such as Aizu in Fukushima Prefecture. Beyond its native distribution it has been introduced to Germany, where it is recorded as naturalized, with additional collection records from Norway. Recognized infraspecific taxa include Geum japonicum var. chinense F.Bolle.
In horticulture the species is grown easily in moderately good, well-drained garden soil enriched with organic matter, and tolerates a wide range of soil textures from sandy to clay. It accepts mildly acid through mildly alkaline pH and prefers consistently moist conditions in either semi-shade or full sun. It is hardy in roughly USDA zones 6-9 (UK zone 7) and flowers in June and July, with seed ripening through July and August. Propagation is straightforward from seed sown in spring or autumn in a cold frame, or by division every three to four years; the species hybridizes freely with other Geum species in cultivation.
Geum japonicum has a long history of use in East Asian traditional medicine. The whole plant is regarded as diuretic and astringent and has been used, often cooked with other foods, for coughs and haemoptysis, while the roots are applied externally as a poultice for boils and ulcers. The leaves are also recorded as edible, although the species earns only a modest edibility rating in cultivation references. Modern phytochemical and pharmacological studies have isolated polyphenols, ellagic acid and a series of tannins (gejaponin A-G) from the plant, and have reported cardioprotective, anti-platelet, neuroprotective, antidepressant-like and hematopoietic-supporting activities in laboratory models.
Common names
Asian Herb BennetMore information about Asian Herb Bennet
How difficult is Asian Herb Bennet to grow?
Geum japonicum is generally considered easy to grow. Plants For A Future and Useful Temperate Plants both describe it as easily grown in moderately good, well-drained garden soil, with the only notable horticultural quirk being that it hybridizes freely with other Geum species when planted nearby. No special equipment or technical skill is required beyond basic perennial care.
How big does Asian Herb Bennet get?
Mature plants reach roughly 0.6 m (2 ft) tall, growing from a basal rosette of leaves typical of the genus Geum. Flower stalks are wiry and emerge above the foliage in early summer.
How often should I water Asian Herb Bennet?
Geum japonicum prefers consistently moist soil rather than dry conditions. Plants For A Future lists 'moist soil' as the preference, and Useful Temperate Plants emphasizes well-drained but organic-rich soil that retains some moisture; it is not drought-tolerant and not aquatic.
What soil is best for Asian Herb Bennet?
The species tolerates light (sandy), medium (loamy) and heavy (clay) soils, ideally well-drained and enriched with organic matter. Soil pH from mildly acid through neutral to mildly alkaline is acceptable, making it adaptable across most garden soils.
What temperatures does Asian Herb Bennet tolerate?
Geum japonicum is hardy across roughly USDA zones 6-9 (UK zone 7). At the genus level, Geum species remain evergreen except where winter temperatures fall below about −18 °C (0 °F), which corresponds to the cold limit of the species' useful range.
How does seasonal care change for Asian Herb Bennet?
Plants typically remain evergreen through mild winters and only die back where temperatures drop below about −18 °C (0 °F). Flowering occurs in June and July with seed ripening in July and August, and clumps benefit from division every three to four years in spring or autumn to maintain vigor.
When does Asian Herb Bennet bloom?
Geum japonicum produces yellow flowers on wiry stalks during June and July, with seed ripening from July into August. The genus Geum overall is known for flowers in shades of white, red, yellow and orange in midsummer.
Are there varieties of Asian Herb Bennet?
A recognized infraspecific taxon is Geum japonicum var. chinense F.Bolle. The species also has several historical synonyms including Geum iyoanum Koidz., Geum sieboldii Scheutz, and Geum japonicum f. iyoanum (Koidz.) H.Ikeda.
How do I grow Asian Herb Bennet outdoors?
The species is suited to outdoor garden cultivation, where it is easily grown in moderately good, well-drained soil enriched with organic matter. It accepts either semi-shade or full sun and is hardy through roughly USDA zones 6-9. Note that it hybridizes freely with other Geum species, so seed-grown offspring may not come true if other Geum varieties are present.
How do I propagate Asian Herb Bennet?
How is Asian Herb Bennet pollinated?
Flowers are insect-pollinated (entomophilous). At the genus level, Geum species also serve as larval food for some Lepidoptera.
Is Asian Herb Bennet edible?
The leaves of Geum japonicum are recorded as edible, although Plants For A Future gives the species a modest edibility rating of 1 out of 5 and provides no specific culinary preparations beyond noting that the plant is harvested from the wild in Japan for local use.
What are the medicinal uses of Asian Herb Bennet?
Geum japonicum has a long history in East Asian traditional medicine. The whole plant is regarded as diuretic and astringent and has been cooked with other foods to treat coughs and haemoptysis, while the roots are applied externally as a poultice for boils and ulcers. Modern pharmacological studies have isolated polyphenols, ellagic acid and a series of tannins (gejaponin A-G) and have reported cardioprotective, anti-platelet, neuroprotective and antidepressant-like activities in laboratory models, though clinical evidence remains limited.
Are there other uses for Asian Herb Bennet?
No notable non-medicinal, non-culinary uses are recorded. Plants For A Future rates the species 0 out of 5 for 'other uses'.
What is the region of origin of Asian Herb Bennet
What is the sunlight requirement for Asian Herb Bennet
Is Asian Herb Bennet toxic to humans/pets?
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