Hortensia, a shrub with fabulous bloom clusters

Hortensia

Hortensia, more commonly known as hydrangea, is a wonderful flower shrub.

Key facts to remember

NameHydrangea
FamilyHydrangeaceae
Height – 3 to 6 ½ feet (1 to 2 meters)

Exposure – part sun and shade
Soil – more on the acidic side, heath soil

Foliage – deciduous –  Flowering – June to October

Here are our pruning, growing and care techniques to spur nice growth for your hortensia as seasons come and go.

Exposure for hortensia

Hortensia exposureIt’s important to give your hortensia all the chances it can get to grow well.

  • Hortensia appreciates sunlight, on the condition that it never gets scorching hot, especially in summer.
  • Morning or evening sun is the best light for a hortensia.

The hortensia shrub starts unfurling its leaves early on in season, usually at the beginning of spring.

  • To protect it from late frosts, try to plant it along the wall of a house, or under a tree that will cover it from the last frosts of the year.

Note also that Hydrangea paniculata deals with cold weather much better than the most famous hortensia: Hydrangea macrophyla.

How to plant hortensia

Like most shrubs, hortensia is preferably planted in fall.

Planting hortensiaFor 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.

  • It needs heath soil to provide it with acidity, and soil mix or garden soil to grow well.
  • A mix of 50% heath soil and 50% soil mix or garden soil is ideal.
  • If your soil is full of limestone, avoid planting hortensia altogether, or add a lot of sand to lighten up the soil.

If you are hoping to see your hortensias thrive, plant them 30 to 40 inches (75 to 100 cm) apart.

  • Make sure the root crown (portion of the tree located between the trunk and roots) is at ground level, not below it.
  • Press the soil down well upon planting.
  • Water regularly, especially during the first year after planting your hortensia.
  • Check out more tips on how to plant heath plants.

Pruning and care for hortensia

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.

  • After flowering, remove wilted flowers regularly (deadheading).
  • Prune hortensia after freezing is over, in March.
  • We’ve got a snappy Smart tip Tutorial video to prune hortensia

Keeping your hortensia blue:

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.

  • Heath soil upon planting is one of the most effective ways to keep them blue.
  • 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.
  • Shale mulch or pine bark mulch also contribute to increasing soil acidity.

Blue hortensia

Learn more about hortensia

Hydrangea macrophyla is the most common and well-known hortensia, but there are many more.

Hortensia paniculataShrubs 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.

Hortensia diseases

Hortensia diseaseHortensia 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.

  • This is a classic case of chlorosis: enrich the soil with hortensia-specific fertilizer and add as much heath soil topdressing you can muster.

Smart tip

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.