UK propagation guide · RHS timing
How to propagate hydrangea in the UK
Why the British answer differs
The British calendar puts this window in late summer, when the light is already going. That is why the RHS says summer cuttings seldom need bottom heat but autumn ones root faster with it — the same cutting, two months apart, is a different job here.
What to root hydrangea in
50% free-draining peat-free potting compost to 50% sharp sand.
Summer cuttings seldom need bottom heat. By autumn they root noticeably faster in a heated propagator, which is the difference a British September makes.
How long it takes
Quick for cuttings taken in summer; slower as the light goes.
More hydrangea care for British gardens
Care at a glance
Propagating hydrangea in the UK — FAQ
When should I propagate hydrangea in the UK?
Late summer to mid-autumn, from this season’s growth once the base of the stem has firmed up while the tip is still soft. Take 10-15 cm (4-6 in), cutting just below a leaf node. The British calendar puts this window in late summer, when the light is already going. That is why the RHS says summer cuttings seldom need bottom heat but autumn ones root faster with it — the same cutting, two months apart, is a different job here.
What compost should I use for hydrangea cuttings in Britain?
50% free-draining peat-free potting compost to 50% sharp sand. RHS propagation guidance specifies peat-free media throughout, and most British retailers now stock peat-free as standard. The mix matters more than the brand: cuttings rot in anything that holds water, which is why the RHS ratios lean so heavily on sharp sand and grit.
Do I need a heated propagator for hydrangea in the UK?
Summer cuttings seldom need bottom heat. By autumn they root noticeably faster in a heated propagator, which is the difference a British September makes.
How long does hydrangea take to root?
Quick for cuttings taken in summer; slower as the light goes.
Why is UK propagation timing different from American advice?
Most propagation guides online are written for warmer, brighter conditions where a windowsill will root a cutting on its own. British gardening organises the year differently — softwood in spring, semi-ripe in late summer, hardwood over winter — and the RHS specifies bottom heat of 18-24°C (64-75°F) for softwood cuttings, which an average unheated British room does not reach. British winter light is the other constraint: the same cutting that roots in three weeks in June can sit for three months from a November windowsill.
Can I propagate hydrangea the same way as the American guides say?
The technique is usually the same — stem-tip cutting (with a node) or air layering. What changes here is when you do it, what you root it in, and whether you need heat. Our hydrangea propagation guide covers the general method; this page covers the British calendar and conditions.