Hydrangea serrata thunbergii

Common name:   Family: Hydrangeaceae
Author: Siebold. Botanical references: 11, 200
Known Hazards: None known
Range: E. Asia – Japan.
Habitat: Montane woodlands and by mountain streams all over Japan11, 174.
Edibility Rating (1-5): 3 Medicinal Rating (1-5): 0
Epithets: From a Dictionary of Botanical Epithets
serra = toothed; serrata = saw toothed;
Systematics: From a UDSA Plants Database
Order: Rosales. Hydrangea family

Physical Characteristics

A decidious shrub growing to 1.5m. It is hardy to zone 6 and is frost tender. It is in flower from July to August. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Bees. We rate it 3/5 for edibility and 0/5 for medicinal use.

The plant prefers light (sandy), medium (loamy) and heavy (clay) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It requires moist soil. The plant can tolerates strong winds but not maritime exposure.

Habitats and Possible Locations

Hedge, Woodland, Sunny Edge, Dappled Shade.

Edible Uses

Leaves; Sweetener.

The young leaves, after fermentation

174, become very sweet and are used to make a sweet tea called ‘tea of heaven’, it is used in Buddhist ceremonies11, 46, 61. The leaves contain phellodulcin (its chemical formula is C16 H14 O), a very sweet substance that can be used as a sugar substitute116, 183. The older leaves can be dried, powdered and used as a flavouring on foods105, 177. The young leaves and shoots are also eaten cooked105, 177.

Medicinal Uses

None known

Other Uses


Can be grown as a low hedge

29, it is quite wind tolerant.

Cultivation details

Tolerates most soil200, thriving in a well-drained loamy soil1, but resenting dryness at the roots11, 200. Succeeds in full sun or semi-shade200, but if it is grown in a low rainfall area then it requires shade at the hottest part of the day11. Does well on very acid soils with a pH around 4.5200. The colour of the flowers reflects the pH of the soil the plant is growing in, the flowers are pink in a neutral to alkaline soil and blue in an acid soil. Plants are hardy to about -25°c when dormant but the young growth in spring can be killed by late frosts. This species is notably susceptible to honey fungus200.


Seed – surface sow in a greenhouse in spring113. Cover the pot with paper until the seed germinates78. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Cuttings of half-ripe wood, 8cm long, July/August in a frame. Overwinter in a greenhouse and plant out in late spring78. Cuttings of mature wood in late autumn in a frame200. Mound layering in spring. Takes 12 months78. Leaf-bud cuttings of the current seasons growth in a frame200.