Blue bloom clusters that shift to pink on chalky ground, others carried on a magnificent panicle, on a shrub of 3 to 6½ feet: that is hortensia, or hydrangea (Hydrangea macrophyla being the best known of them), a flower shrub asking virtually no care. Give it acidic heath soil and sun that never scorches, and the flowering runs from summer to fall.
| Name | Hydrangea |
|---|---|
| Family | Hydrangeaceae |
| Height | 3 to 6 ½ feet (1 to 2 meters) |
| Soil | more on the acidic side, heath soil |
| Exposure | part sun, shade |
| Foliage | deciduous |
| Flowering | summer → fall |
Here are our pruning, growing and care techniques to spur nice growth for your hortensia as seasons come and go.
It’s important to give your hortensia all the chances it can get to grow well.
The hortensia shrub starts unfurling its leaves early on in season, usually at the beginning of spring.
Note also that Hydrangea paniculata deals with cold weather much better than the most famous hortensia: Hydrangea macrophyla.
Like most shrubs, hortensia is preferably planted in fall.
For plants that have been purchased in pots or containers, it’s possible to transplant until spring and even summer as long as both hot and cold spells are avoided.
If you are hoping to see your hortensias thrive, plant them 30 to 40 inches (75 to 100 cm) apart.
It’s a well-known fact that care is truly easy. Virtually no maintenance is required at all, except for an annual pruning that will let the shrub bear even more flowers.
Most persons who discover that their hortensia shifted to a pinkish color nearly always have an issue with soil acidity.
The more chalk and limestone soil contains, the more difficult it is to keep your hortensia blue.
The solution? To keep your hortensia blue, you must make the soil more acidic.
Others possibilities include alum rock powder, it contains aluminum sulfate that will quickly lead to new, blue flowers. Sometimes it’s available in liquid form in garden stores.
Hortensia is not a single plant but a whole group, from compact shrubs to self-clinging climbers. The three types described here are chosen on hardiness and on the place you have to fill.
| Hortensia | What sets it apart | Cold tolerance | Where to plant it |
|---|---|---|---|
| Hydrangea macrophyla | The most common and best-known hortensia | Hardy, but the least tolerant of the three | Sheltered beds, along a house wall against late frosts |
| Hydrangea paniculata | Bloom clusters carried on a magnificent panicle | Copes with cold far better than macrophyla | Open garden positions in colder gardens |
| Climbing hortensia | A full-blown climber rather than a shrub | Hardy, like all hortensia | To dress a North-facing wall |
Planting several different types in different corners is the simplest way to spread colour through the garden.
Hydrangea macrophyla is the most common and well-known hortensia, but there are many more.
Shrubs of variable size, some of which are even full-blown climbers, make hortensia a great choice for gardens. They’re virtually everywhere in old Europe, and plentiful across the planet, too.
Pretty hardy plants, all hortensia resist temperatures down to 5°F (-15°C) and some even cope well with -30°F (-30°C).
On the picture to the right, a magnificent hortensia paniculata.
To dress a North-facing wall, plant a climbing hortensia there.
Beyond the three main types, a handful of named varieties turn up again and again in garden centres and catalogues. Here is how the most widely grown ones compare on colour, size and the job they do best.
| Variety | Type | Flower colour | Best use |
|---|---|---|---|
| ‘Limelight’ | Paniculata, large panicles | Lime green to cream, pink tints | Back of border, informal hedge |
| ‘Bobo’ | Dwarf paniculata | White ageing soft pink | Pots, small gardens, low edging |
| ‘Pinky Winky’ | Paniculata, two-tone panicles | White tips over deep pink base | Open sunny bed, long display |
| ‘Nikko Blue’ | Macrophylla mophead | Strong blue on acid soil | Heath soil bed, coastal gardens |
| ‘Snow Queen’ | Oakleaf, upright panicles | White, with red autumn foliage | Woodland edge, autumn interest |
| ‘Endless Summer’ | Macrophylla mophead, repeat flowering | Blue on acid soil, pink on chalk | Sheltered bed or large pot |
| ‘Annabelle’ | Arborescens, rounded heads | Pure white, ageing green | Shady border, cut and dried flowers |
| ‘Vanille Fraise’ | Paniculata, conical panicles | White turning strawberry pink | Feature shrub, colder gardens |
Hortensia is relatively resistant, but it nonetheless does have a few disease-triggering weaknesses.
If white balls appear along the stems, you are certainly facing an invasion of scale insects.
If whitish felt covers the underside of leaves, it is surely an attack of powdery mildew.
If your soil is too chalky, your hortensia will quickly show signs of stress and turn yellow.
Plant several different types of hortensia in different places throughout the garden: you’ll be surprised at how they contribute to adding color and beauty to your garden.
