Heptacodium


Heptacodium miconioides has the common name 七子花 qi zi hua in Standard Chinese - of which the English common name Seven Son Flower is a translation. It is a member of the family Caprifoliaceae, a cousin of the honeysuckle, and the sole species of the monotypic genus Heptacodium.
Endemic to China, this species was discovered in 1907 growing on mountain cliffs at 'Hsing-Shan Hsien' in present day Xingshan County in the west of Hubei Province in central China by Ernest Wilson whilst collecting on behalf of the Arnold Arboretum. Considered rare even at that time, only nine populations are known to remain in the wild, all of them in Anhui and Zhejiang provinces and threatened by habitat loss. The species is now under second-class national protection in China. The Sino-American Botanical Expedition of 1980 collected viable seeds and sent them to the Arnold Arboretum where it was found to be readily cultivated. The plant is now widely grown as an ornamental around the world.

Description

Heptacodium miconioides is a deciduous large shrub or small tree, typically growing to a height of. The bark of the trunk is papery and thin, light tan in colour, and exfoliates in strips or sheets. The upright, spreading, quadrangular branches give the plant a rounded, often irregular shape. The dark-green cordate leaves are opposite, 8–10 cm long by 5–6 cm wide, with entire margins and deeply impressed venation running parallel to the margin.
In September, H. miconioides produces large shows of small fragrant white blooms attractive to butterflies and bumblebees, the flowers five-petalled, < 13 mm across. When the white corollas have fallen, the calyces develop into deep red expanded lobes which persist into November. The plant may be found in scrub, woodlands, and on the margins of broadleaved evergreen forests, often on cliffs, at altitudes of 600-1000 metres.

Six flowers, not seven

Noted plantsman John Grimshaw, director of the Yorkshire Arboretum, relayed the following observation of H. miconioides from distinguished botanist Allen J. Coombes, :
'Seven' is actually misleading, for the flowers in each capitulum are held in two rows of three clustered around a central bud, which is not a flower bud but in fact a continuation of the inflorescence axis, which will push up as the flowers fade and develop a new ring of six flowers, again around a central bud. Three such iterations have been observed.

Cultivation

Readily propagated from either seed or by softwood cuttings, the species has since become widely available in North America and Europe, and was stocked by 26 nurseries in the UK alone in 2011. H. miconioides is extremely hardy, and tolerant of temperatures as low as. It is also fast-growing, and can reach a height of in just five years; it is also very shade tolerant. This plant has gained the Royal Horticultural Society’s Award of Garden Merit.

Notable trees

In the UK, a specimen 8 m high planted in 1981 grows in the Flagpole Bed alongside Jermyn House at the Sir Harold Hillier Gardens, Ampfield, near Romsey.

Etymology

The generic name of Heptacodium has sometimes been said to mean 'seven bells', but was in fact coined by Arnold Arboretum taxonomist Alfred Rehder from the Greek κώδειά - 'poppy head' with the prefix έπτά 'seven', giving the meaning 'having seven structures resembling poppy heads'. The specific epithet miconioides alludes to the similarities of the plant to certain species belonging to the unrelated genus Miconia.
The common name in Standard Chinese 七子花 is composed of the characters 七 'seven', 子 'son' / 'child' and 花 'flower' - whence 'Seven Son Flower'. Approximate pronunciation 'Chyee-dzu-waa'.

Medicinal potential

Recent tests have demonstrated that extracts from the plant possess antibacterial activity.
The leaf blades of Heptacodium have been found to contain flavonoids, tannins, alkaloids, saponins, lignin and chlorogenic acid.

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