Growing Hydrangea

Hydrangea are a summer flowering shrub, usually deciduous  with large showy flowers.

Hydrangea are easy to grow and require only minimal pruning, which makes them a low maintenance shrub. They are not fussy about soil types and conditions and some, particularly the climbing Hydrangea, will grow in shade. Most Hydrangea are large shrubs from  1.5m - 3m (3-10ft) and so need a fair amount of growing space.

 Hydrangea make great border plants and are grown for their lovely showy flower heads, predominately flowering  pink, mauve, blue, cream and white.  Hydrangea will grow in most soils including chalk, with a preference for sun but Hydrangea will also tolerate partial shade.  In some varieties the flower colour can be affected and changed by the pH of the soil; whether the soil is acid or alkaline. Growing in an acid soil some Hydrangea flowers blue and in alkaline pink; the white flowers are unaffected.

Hydrangea are a woodland plant with a preference for moist but well-drained soil in sun or semishade. As a woodland plant, they are best planted with some shade and in a position which avoids full afternoon sun. Hydrangea will thrive in the cooler part of the garden.  As always, it is a question of the right plant right place, which means avoid planting where there is hot afternoon sun or cold easterly winds. Generally Hydrangea is tolerant of most growing conditions.

There is a very attractive climbing form of Hydrangea, H. petiorlaris which will tolerate a high degree of shade and can be useful to grow up a shady wall. This really is a lovely climber, relatively fast growing and so tending to be vigorous but with beautiful flowers in the spring. I have seen grown to great effect on a large semi shaded wall where it can be left to grow unchecked and form a mass of white flowers in the spring. It is self-supporting but needs a reasonably large space.

There are also some  varieties of Hydrangea which have scented blooms, such as Hydrangea paniculata 'Wim's Red' and also some compact varieties H. panciulata Little lime ('Jane') and Hydrangea with beautiful delicate colours such as pink turning to white as in Hydrangea paniculata Vanille Fraise ('Renhy')

The range of Hydrangea is wide and varied and quite a few are illustrated below and also on Pinterest board

Hydrangea macrophylla come in two forms: 'Lacecaps' see illustrated below a lovely delicate bloom, and 'Hortensias (mop head ) with rounder flower heads.

When selecting a Hydrangea for the garden many grow to around 3m, such as H.Paniculata 'Unique',  Serrata the popular ''Blue bird' smaller around 1.2m  and there are many Macrophylla varieties around 1.5m. a useful size for most gardens.

green wheelbarrow

Hydrangea is a green wheelbarrow shrub being easy to grow and tolerant of most conditions.

Pruning Hydrangea

You need to decide which type of Hydrangea you have to know how to prune it. H. Mophead and Lacecaps flower on old wood and they are pruned lightly, in spring. Just cut back a few cm down to a bud do not prune hard although you can remove spindly, weak growth. The image drawing below shows the light prune required for Mopheads and Lacecaps.

Hydrangea paniculata, distinguishable by its cone shaped blooms, flowers on the current year's growth (wood) and is pruned much harder in late winter/early spring. This means all the flowers are produced on new steps which grow this season. When you prune H. paniculata you are cutting back to a framework to enable the shrub to make new growth. 

Pruning is not essential to Hydrangea, both Mophead and Lacecap will flower without pruning. The benefit of pruning is to keep the shrub in shape and pruning can improve flowering. 

The time for pruning Hydrangea, (with the exception of the climbing Hydrangea H.Petiolaris, see below,)  is spring.

Sometimes in spring, if there is a bad frost, it can damage the new growth, cut back further to a pair of healthy buds. Also remove any spindly weak stems and on older plants remove a few, 2/3 older stems from the based which will encourage new growth later in the spring.  


How to prune Hydrangea with text

For Lacecap Hydrangea a light prune in February to remove the top of the stems with last season's flower head in place and cut down to just above a green bud which will be showing by now. Do not prune harder, or lower, to do so is a mistake which can prevent the Hydrangea flowering later in the summer.

A climbing Hydrangea should be pruned  immediately after flowering to restrict its growth, cutting back long shoots. It can be pruned harder if needed, but if you are pruning hard it is best to stagger over more than one year because if it is pruned hard all at once,  there may be significantly less flowers the next year.

Hydrangea paniculata and H. arborescens need more attentive pruning, (which maybe why they are less popular.) Each spring prune back to a framework which means cutting back stems to a pair of buds. These varieties flower best if pruned harder so can be cut back to the lowest pair of buds which may result in the plant, post pruning, only being 25cms but you can of course leave several buds on and prune less hard.

The easiest Hydrangea to grow are the Lacecaps and Mopheads as you can simply remove the old flower heads in the spring cutting down to a pair of buds and that's it.


Types of Hydrangea

hydrangea paniculata in bloom

Hydrangea Paniculata

This is Hydrangea Paniculata which needs some pruning  and flowers best if regularly pruned in the spring. It flowers in the late summer producing white or cream flowers. 

Prune as detailed above to maintain flowers otherwise Hydrangea is usually trouble and disease free but comes with a size warning - they can grow quite large up to 7 meters and  5 meters wide,

Hydrangea petiolaris the climbing Hydrangea

Hydrangea Petiolaris the climbing hydrangea

The climbing hydrangea Petiolaris is vigorous, which means fast growing and needs plenty of space. The image left shows how easily it covers most of a wall which means you need a big space for this and it will reward you with fantastic fresh green foliage in spring, (it is deciduous)  and lovely delicate flowers in early summer. If you need to cover a large wall, particularly if it is partially shady, this is a great choice. 

As it is spring flowering, hydrangea Petiolaris should be pruned after it has flowered as it produces flowers on the current year’s growth.  A vigorous, deciduous climber which is fully hardy and self clinging.


Hydrangea macrophylla

The common Hydrangea which group is divided into two groups:  Lacecaps and Mopheads. Some varieties of Hydrangea Serra are also described as lacecaps. It is very confusing best to buy and plant what you like. 

Hydrangea macrophylla light blue

Serrata 'Veitchii'

Image  is Hydrangea  macrophylla 'merveille browning'  Prune in the spring cutting down to flower buds.

Hydrangea Macrophylla  Hortensias is also known as mophead. All  Macrophylla are affected by the PH of the soil acid soils produce blue flowers alkaline pink. 

To be precise, a Ph of less than 5.5 produces blue flowers, more than 5.5 pink.

Hydrangea paniculata fading blooms

The fading blooms of Hydrangeas are very attractive and last for weeks. Left is Hydrangea Paniculata where the limey white blooms are fading through pink to pale white.

Last updated 22.01.20