Hydrangea
Hydrangea macrophylla
An ornamental plant, planted March to May or September to November.
In September: nothing to do. It can be planted now. Wear gloves: it can cause a skin allergy.
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Hydrangea, month by month
Bar: the usual months. Sprout: this month.
| Sowing, planting or job | Sep | Oct | Nov | Dec | 2027Jan | Feb | Mar | Apr | May | Jun | Jul | Aug |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Plant a pot-grown hydrangea. | usual | usual | usual | none | none | none | usual | usual | usual | none | none | none |
| Deadhead the hydrangea. | none | none | none | none | none | none | usual | usual | none | none | none | none |
| Mulch the hydrangea. | none | none | none | none | none | none | usual | usual | usual | none | none | none |
| Prune the hydrangea. | none | none | none | none | none | none | none | usual | none | none | none | none |
What to do, and when
The usual months for a UK garden. Your own plan gives the week.
Handle it with care
Wear gloves: it can cause a skin allergy.
Strong source: RHS.
Planting
Plant a pot-grown hydrangea March to May, and September to November, 90cm to 2.4m apart. Moderate source: RHS.
Deadhead the hydrangea
Usually March to April. Moderate source: RHS.
Mulch the hydrangea
Use leafmould, garden compost or a manure-based soil conditioner to help the soil hold moisture.
Usually March to May. Moderate source: RHS.
Prune the hydrangea
Prune lightly, but regularly.
Usually April. Moderate source: RHS.
What the source words mean
Strong: the RHS page for this plant is among them.Moderate: another trusted UK source, or the RHS on its group.
What not to do
Don’t feed it
It’s usually best not to feed hydrangeas: feeding gives leaves at the cost of flowers.
Moderate source: Gardeners’ World.
Don’t prune it hard
The flowers form on shoots from last year’s stems, so hard pruning loses them.
Moderate source: RHS.
Every line above names the page it comes from. Where we found no good source for a job, we left it out. Where the name “Hydrangea” comes from.