All you need to know about the blue hydrangea

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Blue is beautiful and if you love blue objects, you may want to grow some blue hydrangeas in your garden or balcony. If you love flowers, plants, urban garden, and balcony gardening, you must have heard about hydrangeas. The hydrangea (Hydrangea macrophylla) can bloom in pink, red or blue, and the color depends primarily on the soil PH.

Yes, the beautiful color of the hydrangea is controlled by the pH value of the soil in which it is planted. You can raise the pH value by adding lime and lowering it with weak doses of aluminum sulphate. If the hydrangea is in neutral to slightly acidic soil, it blooms with white, pink or cerise flowers. In lime-poor soils, the flower turns blue.

There are few plants that offer such a flower splendor as the hydrangea. Large, fluffy balls in blue, purple, white or pink with clusters of small flowers. Hydrangea’s large, full-bodied flowers fit just as well in a magnificent bouquet as in your flowerbed. In the garden, it can grow as high as four meters, while the one that grows in a pot rarely grows taller than one meter.

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Hydrangeas bloom in late summer with impressive, colorful flowers. It is a plant that people grow a lot all around the world, mostly as an indoor plant. One reason for its popularity is that this ornamental plant is available in almost 30 different varieties.

The origin of hydrangeas

It was in the 18th century that the hydrangea came to Europe from Japan. Hydrangea has its origins in East Asia as well as in North and South America. The name hydrangea comes from the Greek where it is most easily translated as water container – something that probably has to do with the shape of the plant’s seedling. Macrophylla , in turn, means large-leaved .

It is also said that it was the French botanist Philbert Commerson who introduced Hortensia to Europe. In 1766, he was on a voyage of discovery to Asia where only men were allowed to participate. But Philbert smuggled his beloved Hortense Barré with him, and she dressed herself like a man and pretended to be his servant. During the trip, of course, she was exposed. But in any case, in 1769 they brought with them a beautiful plant back home. And it was named after the beautiful Hortense.

The hydrangea plant – a family with many personalities

In the hydrangea genus alone, there are between 70-100 different species that occur in different shapes and colors. You will find half-shrubs as well as shrubs and small trees in the genus, as well as some that are grown in pots. The hydrangea can grow as an upright plant or as a climbing one. There is a great variety of both fertile and sterile flowers in the different varieties. Among the cultivated varieties, a clear majority of the edging flowers are sterile. These then come in the form of white, blue or red. Fertile flowers, on the other hand, are either white or bluish.

Plant hydrangeas

The hydrangea should be planted out before the frost comes in the winter to get flowers for next year. Be sure to use special hydrangea or rhododendron soil, preferably mixed with a little peat.

Place the hydrangea in a place where it gets light but is still semi-shady. Be sure to avoid places with too much heat or direct sunlight.

Water abundantly in the pit or pot before putting the plant down. Even then, your hydrangea needs to be moist. So make sure you water before it dries out. You can advantageously add some low-calcium nutrients to the water.

Make sure you carefully insulate the leaves or similar materials before winter.

Do not cut your hydrangea too hard as many varieties will re-bloom on old parts of the plant

Growing hydrangeas – tips and advice

Growing hydrangeas require the right conditions. If your garden has sandy soil and summers don’t see enough rain, growing hydrangeas can be challenging. The hydrangea is an extremely thirsty plant that requires evenly moist soil to survive.

The hydrangea is used as a potted plant indoors during the winter and is nice to place together with other flowering plants in the same color. Feel free to mix some green plant in the group to create harmony and balance. The hydrangea can also be used as a cut flower and is effective alone in a beautiful vase. During the summer, you can move the hydrangea onto the balcony or terrace. Then care is facilitated if it is replanted in a larger pot. You may also want to co-plant it with some ivy that can hang down over the pot edge.


Thrives in bright windows without direct sunlight. The hydrangea can stand cool, down to 15 degrees. The flowers then last even longer. Make sure it is shielded from strong sun during the flowering period. It thrives at room temperature.


Hydrangea wants plenty of water. When it blooms, the soil should be moist at all times. It is something you can easily feel by putting a finger in the soil. The slightest sign that it is too dry, it’s time to water. If it gets too dry, both flowers and buds will start to fall off, and the leaves will take on a brown color. If you have let your hydrangea dry out, it can also be difficult, and sometimes even impossible, to bring it back to life.

However, if there is an excess of water, you need to pour it away immediately. After all. Blue objects need care as everything else. Feed the plant every two weeks during the summer and cut off withered flowers afterwards. Do not spill too much water on the flowers, as they can easily become discoloured, and you may lose your beautiful blue objects.


Hydrangea is a sour soil plant and dislikes lime. From spring until summer, you can advantageously give your hydrangea potted plant nutrients once a week. For those of you who love blue objects and have blue hydrangeas, you need to make sure that the soil has a low pH value for the flowers to retain their blue color. A normal pH value is sufficient for the color preservation of the pink, red and white hydrangeas.


When your hydrangea has stopped flowering for a while, you can advantageously cut off the flower clusters and about two leaves below them. You may want to hang and dry these as a cut flower if you want something that is a popular decoration in many homes.

Thrives well outdoors

When summer comes, hydrangeas thrive outdoors. Replant in larger pots with hydrangea soil and place in partial shade on the terrace or balcony. The hydrangea can also be planted in the flowerbed in a sheltered position for flowering next year.

After flowering, the hydrangea can be planted out in the garden if it has been in a pot. Place it in warm place and cover it in winter when it gets cold.

Species facts – short points

· The species can grow up to 4 meters high and 3 meters wide.

· As an indoor plant, however, it does not grow taller than 1 meter.

· Blooms from March to September.

· The hydrangea genus has up to about 70-100 different species.

· The color of the flowers depends on the pH value of the soil.

· The hydrangea is very sensitive to drought and wants it to be constantly moist.

Do you remember we told you that you can influence the color of the flower through the pH value? Read a little more about it.

Preventing Blue turning red

Afterall it was your love for blue objects that you opted for blue hydrangea and you will not want to lose the blue colored flowers. Unfortunately, if soil Ph is not maintained, blue flower varieties may not retain their blue color, but become more and more reddish over the years. To prevent blue hydrangeas from getting a dirty pink color, the soil where the hydrangea grows must be acidic. The soil needs to have a pH value of between 4.0 and 4.5. You can keep the soil acidic by not using calcium fertilizers where the hydrangea grows, and by avoiding all kinds of fertilizers that contain calcium.

The acidic soil must also contain a fair amount of aluminum. It is best if the hydrangea can absorb the aluminum, as it helps the plant to build up the blue pigments in the flowers.

Only when these two components are combined, i.e. acid soil and a sufficient amount of aluminum, the hydrangea flowers can retain their beautiful blue color. You can also fertilize blue hydrangea varieties with a special fertilizer for blue dyeing of hydrangeas every spring according to the manufacturer’s instructions. The fertilizer contains aluminum sulphate and can usually be mixed into the water when you water the flowers.

Tip: When planting blue hydrangeas, choose a place rich in peat or use soil-improving humic substances. However, you need to add these again every year, as the acidifying humus breaks down naturally in the soil.

Written by Lisa Johnson

Lisa is a writer and digital marketer with years of industry experience. She has had the opportunity to work with well-known publishers and always pours her heart out in her writing. Her love for interior design is well-known among her friends, who love to come to her apartment to see if she’s added yet another vintage mirror or changed her wallpaper. As a writer and marketer, she loves to stay up to date on the latest trends on social media, so when she’s not busy writing or working her marketing magic, you can find her on her couch scrolling through Instagram for inspiration.

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