Hydrangea – facts and care advice

Scientific name (Latin): Hydrangea macrophylla

Family: Hydrangea family (Hydrangeaceae)

Hydrangeas are often divided into garden hydrangeas and indoor hydrangeas. They are botanically similar, but the plants are cultivated at different temperatures. Indoor hydrangeas are indoor plants and not meant to be planted outdoors. Garden hydrangeas are cultivated at colder temperatures, and they are therefore more hardy – they simply tolerate outdoor life better.

Indoor hydrangeas (house hydrangeas) are perfect indoor plants but can be moved out to the balcony or placed in the garden during the summer (when it's above 15 degrees Celsius around the clock). Feed them, for example, with acidic soil fertilizer every other week.

Garden hydrangeas handle outdoor weather better than indoor hydrangeas, and they also thrive best outdoors. Protect the plant with leaves and branches in winter.

Lilac hydrangea is a shrub with cone-shaped flowers that, over time, can be trained into a lilac-like small tree. Lilac hydrangea has an interesting feature – the flowers can change shade throughout the season. They are also relatively hardy (up to zone 4–5).

Climbing hydrangea is a robust and shade-tolerant climber that can fill in large areas. It produces beautiful golden leaves in autumn and is hardy up to zone 4. One of our most impressive climbers in white.

Smooth hydrangea is a late summer shrub originating in America, it blooms with large, round flower clusters. A richly blooming variety is ‘Annabelle’, which is also available in a pink version – ‘Pink Annabelle’. Smooth hydrangeas are often a bit more hardy than other types of hydrangeas and a good choice if you live a little further north.

So, there are many beautiful types of hydrangeas to choose from, but make sure the variety you choose is hardy in your hardiness zone, meaning it survives the climate where you live. Previously, there were only cold-sensitive species of hydrangeas, but now there are varieties that tolerate up to zone 4–5. Most bloom on last year's shoots, but there are exceptions, such as 'Annabelle', which blooms on this year's shoots. Some varieties should be pruned, others not. Read up on the type of hydrangea you choose, and care for it accordingly.

Growing garden hydrangeas at home is perfectly fine. However, it requires the right conditions, and for those with gardens that have sandy soil and experience summers with little rain, it can be somewhat more difficult because the hydrangea is an extremely thirsty plant that requires consistently moist soil to survive.

The best conditions for producing good hydrangea growth are found for those living in plant zone 1-2, but there are also growers who have successfully grown their hydrangeas up to plant zone 4. If you are one of those who have the right conditions for your hydrangeas, you will have a fantastic garden plant to enjoy for many years if you take care of it properly. You also have the advantage that deer are not particularly fond of hydrangeas.

Tip: The color of hydrangeas is easily affected by the PH level of the soil; in more acidic soil, the flowers turn blue. If you want to turn white or pink flowers blue, you can, for example, add water with alum or put some rusty nails in the soil.

• The hydrangea should be planted before the frost arrives in winter to get flowers for the next year. Make sure you use special hydrangea or rhododendron soil, preferably mixed with some peat.
• Place the hydrangea in a location where it receives light but is still in partial shade, and make sure to avoid places with excessive heat or direct sunlight.
• Water generously in the hole or pot before placing the plant. Even after that, the hydrangea needs moisture around it, so make sure you water before it dries out. You can advantageously add a little low-calcium nutrition to the water.
• Make sure to insulate well with leaves or the like before winter.
• Do not prune the hydrangea too hard, as many varieties bloom again on old parts of the plant.

• Placement
  For those who want their hydrangeas to thrive, there are some things to consider when it comes to caring for this plant. For example, it does not do particularly well in direct sunlight but prefers a place that is bright but still in partial shade. The cooler you can keep your hydrangea, the better – but up to normal room temperature is fine. If it gets warmer than room temperature, you risk damaging your hydrangea, as it does not thrive in too much heat.
• Watering
  Water the hydrangea generously without risking too much residual water in the outer pot. If there is excess water, you must pour it off immediately. The soil, on the other hand, should be constantly moist, which you can easily feel by sticking a finger into the soil. The slightest sign that it is too dry means it is time to water. If it gets too dry, both flowers and buds will begin to fall off and the leaves will turn brown. If you have allowed the hydrangea to dry out, it can also be difficult, and sometimes even impossible, to bring it back to life.
• Fertilization
  From spring to mid-summer, you can feed your hydrangea potted plant once a week. If you have blue hydrangeas, you must ensure that the soil has a low pH value so that the flowers retain their blue color, while a normal pH value is sufficient for color preservation of the pink, red, and white hydrangeas.
• Pruning
  When your hydrangea has finished flowering for a while, you can advantageously cut off the flower clusters and about two leaves below them. These can be hung and dried as cut flowers if desired, a popular decoration in many homes.

It's the same plant - Hydrangea macrophylla - that's used both as a garden plant and as an indoor plant. Regardless of where you want your hydrangea, one thing they have in common is that they are very sensitive to drying out – water often to ensure that the soil never gets dry.

Winter Outdoors, Not Indoors

During June, July, and August, it's time to prune the shoots of the garden hydrangea and then plant the plant out if you want it to survive the winter. Preferably use special hydrangea or rhododendron soil when planting, and water well before putting your plant in the ground.

There, it will continue to grow and develop new shoots and buds that will bloom the following year instead. It is good to cover the plant with leaves or the like before winter to protect the buds. If you do not have the option to plant the hydrangea during the winter, you might as well dispose of the plant, as it cannot survive indoors during the winter months.

Within the hydrangea genus alone, there are between 70-100 different species that appear in various shapes and colors. You'll find semi-shrubs as well as shrubs and small trees in the genus, and some that are exclusively grown in pots. Hydrangeas can grow as upright plants or as climbers, and there's a wide variety of both fertile and sterile flowers in the different variants. Among the cultivated varieties, a clear majority of the marginal flowers are sterile. These then come in covers of white, blue, or red. Fertile flowers, on the other hand, are either white or bluish.

It was in the 18th century that the hydrangea came to Europe from Japan, and the hydrangea originated in East Asia, as well as in North and South America. The name hydrangea comes from Greek, where it most easily translates to water container – which probably has to do with the shape of the plant's seed plant. Macrophylla, on the other hand, means large-leaved.

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