Diamond Rouge Hydrangea

Diamond Rouge Hydrangea (Hydrangea paniculata 'Diamond Rouge') carries the deepest red flower of any panicle hydrangea we grow. Large conical heads open creamy white in early summer, then shift through pink to a strong ruby red as the season goes on. It settles at about 1.5m tall and 1.2m wide, which keeps it in scale with a suburban bed or a large pot.

Why you'll love it

• One shrub, three colours. The heads open creamy white, age through soft pink and finish deep red, holding on the bush for months.
• It takes more sun than a mophead. As a panicle type it flowers well in full sun in cooler districts, where big leaf hydrangeas wilt by lunchtime.
• The colour is stable. Unlike blue and pink mopheads, panicle hydrangeas do not change with soil pH, so what you see is what you get.
• Frost hardy and wind tolerant. It handles cold southern winters unprotected, and the stems hold heavy heads upright in an exposed spot.
• Autumn colour to finish. The foliage turns before it drops, extending the display past the flowers.

Where it works best

Feature planting. A single plant carries a bed on its own from December through to autumn. Give it 1.2m of clear width.

Mass planting and borders. Plant 1.2m apart for a full run. The shrubs meet without crowding, and the colour shift moves across the whole planting at once.

Pots and containers. A pot 500mm or wider holds it closer to 1m. Be realistic about watering, because a potted hydrangea needs a drink most days in summer.

Growing Diamond Rouge Hydrangea in Australia

Position and climate. This suits cool temperate and warm temperate gardens: Melbourne, Canberra, Adelaide, Hobart, the tablelands, Perth and coastal New South Wales. Cooler districts can give it full sun. Where afternoons are hot, morning sun with afternoon shade is safer.

Soil. Rich, moisture retentive and well drained. Dig compost through the bed before planting and mulch 75mm deep, kept clear of the stems. Soil pH does not affect flower colour here.

Water and feed. A thirsty shrub that tells you loudly when dry, wilting in the heat and recovering overnight. Deep soak two or three times a week through summer. Feed a slow release fertiliser in early spring.

Pruning. This is the key difference from a mophead. Panicle hydrangeas flower on new wood, so prune in late winter while bare, cutting last season's stems back by a third to a half.

What to expect when it arrives

It is grown in 200mm pots sold in packs of six and 250mm pots sold in packs of three. Both arrive as young branched plants rather than the shoulder height shrubs you see in a display garden, and both reach full size in roughly two to three seasons.

One thing to expect: this is a deciduous shrub, so an order arriving in winter will be bare sticks with visible buds, and that is a healthy dormant plant rather than a dead one. Plants are delivered Australia wide, with delivery from $29.95. Expect a proper display in the second season, backed by our 30 day healthy plant guarantee.

Plant care guides and related reading

• Understanding hydrangea colour and growth
• Browse the full hydrangea range
• Shrubs and trees with autumn colour
• Plants suited to partial shade

Common questions

Is it safe around cats and dogs?

No. All hydrangeas contain compounds toxic to cats and dogs if the leaves or flowers are eaten, typically causing vomiting and stomach upset. Plant it out of reach of a pet that chews foliage.

When should I prune it?

Late winter, while it is still bare, cutting the previous season's stems back by a third to a half. It flowers on new wood, so this is the opposite of a big leaf hydrangea.

Can I change the flowers to blue?

No, and that is a good thing here. Panicle hydrangeas are not pH responsive, so no soil treatment will shift them. The white to pink to red sequence happens on its own.