Planting Hydrangeas

When to plant hydrangeas?

Hydrangeas are best planted in early autumn, in September or October. This is the ideal time as the soil is still warm and rainfall becomes more frequent, allowing them to establish well before winter. Planting is also possible in spring (March – April), once the main frost periods have passed. Finally, it remains reasonable to plant in early summer, provided watering is carefully monitored.

Where to plant hydrangeas?

Position your hydrangea in a spot where it will receive morning sun or late afternoon sun. In the south of the country, it’s best to shelter it from midday sun. Place it, for example, at the base of a wall or in the dappled shade of a tree.

Choose a location where the soil remains fairly moist, even in summer, and in slightly acidic soil for most varieties, with the notable exception of shrub hydrangeas, which tolerate neutral soil well. If your soil is chalky, add plenty of ericaceous compost to the soil, as well as compost when planting: hydrangeas thrive in rich, humus-rich soils.

Plant your hydrangea preferably in a sheltered spot away from wind.

Note, however, that growing conditions vary depending on the species. Indeed, Hydrangea macrophylla and serrata are better suited to shady, cool locations. They are perfect in woodland settings, for example, alongside ferns or hostas. Conversely, Hydrangea paniculata and arborescens enjoy sunny positions and are relatively drought-tolerant. They don’t strictly need acidic soil and can even grow in moderately chalky soil. You could also choose a climbing hydrangea (Hydrangea petiolaris) and position it against a north-facing wall.

How to plant your hydrangeas?

How to Plant Them in the Ground?

To successfully plant your hydrangeas in the garden:

• Soak the root ball in a basin of water to rehydrate it, until air bubbles disappear.
• Work the soil to a depth of at least 40 cm, adding compost and ericaceous compost if needed. A good base fertiliser (such as dried horn or blood meal) will encourage establishment and nourish your plant without risk of burning. If your soil is dry, you can mix a water retentive gel into the soil when planting.
• Tease out the roots of the root ball if necessary to prevent root girdling (when roots circle around the root ball).
• Position your hydrangea in the planting hole, ensuring the top of the root ball sits 2–3 cm below ground level (a horizontally placed stick is a useful guide).
• Cover the root ball with soil and firm gently.
• Create a shallow watering basin around the base.
• Water regularly after planting and during summer months, and consider applying a layer of mulch to keep the soil cool.

How to Plant Them in Pots?

Hydrangeas are easy to grow in containers. Use a sufficiently wide and deep pot (40–50 cm in all directions), filled with a mix of compost and ericaceous compost. Water frequently and apply fertiliser regularly.

Don’t hesitate to plant hydrangeas in pots—it’s also a solution for chalky soils!

How to care for hydrangeas?

After planting, you will need to:

• Monitor watering, as hydrangeas are sensitive to drought. Water regularly during summer and mulch to keep the soil cool.
• At the end of summer, once flowering has finished, we recommend leaving the dried flower heads as they protect the terminal shoots from winter cold.
• Prune your hydrangeas in late winter, around March. To do this, cut just above well-formed buds, remove damaged or dead branches using secateurs, and thin out by removing some branches from the centre of the shrub with loppers. You can prune more severely to maintain a compact shape, but this will affect that year’s flowering. You will then need to wait until the following year to enjoy abundant blooms again.