Hydrangea, Mountain Hydrangea, Sawtooth Hydrangea
Hydrangea serrata

Family: Hydrangeaceae

What it is like

Bloom Color: Blue, Pink. Main Bloom Time: Early summer, Early spring, Late summer, Late spring, Mid summer, Mid spring. Form: Rounded.

Hydrangea serrata is a deciduous Shrub growing to 2 m (6ft) by 1 m (3ft 3in) at a medium rate. See above for USDA hardiness. It is hardy to UK zone 6 and is not frost tender. It is in flower from July to August. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil. The plant can tolerates strong winds but not maritime exposure.

Height (m): 2

Where it is found

Woodland to 1500 metres in the mountains of C. and S. Japan.

E. Asia - Japan.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 2

Young leaves and shoots - cooked. These leaves do not become sweet like those of sspp thunbergii or amagiana or those of H. macrophylla.

Medicine

Rating: 0

Other

Rating: 3

Can be grown as a low hedge, it is quite wind tolerant.

Hedge: Plants that can be grown as hedges.

Hedge: Hedge

How it is grown

Landscape Uses:Container, Seashore, Specimen. Tolerates most soil, thriving in a well-drained loamy soil, but resenting dryness at the roots. Succeeds in full sun or semi-shade, but if it is grown in a low rainfall area then it requires shade at the hottest part of the day. Does well on very acid soils with a pH around 4.5. Tolerates alkaline soils, but it may become chlorotic on shallow soils over chalk. 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. A very ornamental plant, there are many named varieties. Considerable difficulties exist in the nomenclature for this species and H. microphylla. They are treated here in accordance with "Bean's Manual of Trees and Shrubs", though many botanists view H. serrata as no more than a sub-species of H. macrophylla. This species is notably susceptible to honey fungus. Special Features: Not North American native, Blooms are very showy.

Propagating it: Seed - surface sow in a greenhouse in spring. Cover the pot with paper until the seed germinates. 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 spring. Cuttings of mature wood in late autumn in a frame. Mound layering in spring. Takes 12 months. Leaf-bud cuttings of the current seasons growth in a frame.

Best place to grow: Woodland Garden Sunny Edge; Dappled Shade; Shady Edge; Hedge;

Habit: Shrub

Hardiness: 5-9

Growth: Medium

Soil: Light (sandy), medium, heavy (clay)

Shade: Semi-shade, no shade

Moisture: Moist

Things to keep in mind

Its other names

Local names

Synonyms

H. macrophylla acuminata.