Hydrangea paniculata Pink Diamond 'Interhydia' and Hydrangea paniculata 'Interhydia'.



Common name/s ?

Paniculate hydrangea 'Pink Diamond' and plumed hydrangea 'Pink Diamond'.

Skill rating



Asia (China, Japan and Korea).

Type of plant ?

Deciduous, perennial shrub.

Hardiness zone ?

RHS zone


EGF zone


USDA zone


Eventual size

To 3m height and 2.5m spread.

Growth rate ?

Moderate, will reach its full size in 5 to 10 years.

Shape it grows into

Upright, open shrub.

Season/s of interest

Flowers from the middle of summer through to autumn.

Where to grow it

Happy in full sun or part shade.
Prefers well drained to moist soil.

Happy in most soil types, but won’t tolerate chalky or alkaline soil. Will tolerate exposed or sheltered positions of any aspect.

Hydrangea paniculata 'Pink Diamond'


A deciduous, open shrub which bears large panicles of creamy white flowers in summer, which mature to a deep pink colour in autumn. The flowers eventually fade to a pinky-brown but can be retained over winter to extend the period of interest.

What to use it for

Works well in beds and borders with a cottage garden or woodland theme. Can be container grown, but this works best when it is trained to be a standard. The flowers are useful for flower arrangements, either fresh or dried.

How to look after it

Once mature this plant will be relatively drought tolerant, but it would still benefit from a good organic mulch over the rooting area in spring. Water well in dry spells while the plant is young.

How to prune it

Pruning isn’t essential, but the harder the plant is pruned the larger the flower panicles will be (albeit that there may be fewer of them and flowering may start later).

Prune in late summer/early spring while the plant is still dormant and not actively growing. Cut the plant back to a basic, woody framework which can be down to 25cm, although you may wish to keep it taller (around 60cm) if it’s at the back of a border. In subsequent years cut the plant back to the pair of buds which are just above this framework. Overgrown plants can be renovated by hard pruning to form this low framework. As Hydrangea paniculata flowers on this year’s wood, hard pruning will not prevent flowering.

Alternatively, train into a standard form, though the stem will need additional support to hold the weight of the canopy.

How to propagate it

Take softwood cuttings from late spring to midsummer and semi-ripe cuttings in midsummer. The cuttings should take easily and root within 4 weeks.

Common problems

May be susceptible to leaf spots, powdery mildew, iron deficiency and root and foot rots. The flowers can be affected with the grey mould Botrytis cinerea (known as hydrangea stem and leaf rot). Aphids, capsid bugs, stem eelworms and hydrangea scale may be a problem. Viruses may also be a problem, the hydrangea ringspot virus affects leaves and stems and other viruses can cause the flowers to stay permanently green.

Other useful information

The name ‘hydrangea’ derives from the Greek words ‘hydro’ and ‘aggos’ meaning ‘water jar’; referring to the cup-shaped form of the fruit capsules. Hydrangea paniculata was identified and named in 1829 by German physician and botanist Philipp Franz von Siebold while working in Japan.

This plant has been given the Award of Garden Merit by the RHS.

Most parts of this plant are toxic if ingested and external contact may aggravate skin allergies.