If you love a romantic bed design in which the flowers of the plants impress with harmonious colors one year and create colorful color contrasts the next year, hydrangeas are the right choice for you. The relatively easy-care hydrangea naturally blooms mostly pink, but depending on the soil the color of the flowers can change to purple, blue or red. In order to maintain the pure flower color, some care may be necessary.
How to keep my hydrangea pink?
To get a pink hydrangea, make sure the soil has a pH of around 6. In acidic soil (pH below 6) it blooms blue, in alkaline soil (pH above 7) it appears red. Test sticks help to determine the pH value and adjust it if necessary.
Pink turns to blue
It is not unusual and is what makes this plant particularly attractive that many hydrangeas have different colored flower umbels and that the individual flowers are sometimes even multicolored.
The pH value of the soil and the aluminum content of the soil are responsible for the different colors. Only when this value is around 6 will the hydrangea be decorated with pink flower umbels. If the value is below this, the soil is said to be acidic and the hydrangea changes its flower color to blue. On alkaline soils with a pH value above 7, the color often changes to a rich red.
Preserve the original color
So that the hydrangea does not change color undesirably and its delicate flower color is retained, you must ensure that the soil has a pH value of around 6. You can analyze for yourself whether you have acidic or alkaline soil in your garden using test sticks (€6.00 on Amazon).
If you need to raise the pH value slightly, you can deacidify soils that are too acidic by regularly applying lime.
If, on the other hand, your garden soil has an alkaline pH value of over 6.5, you can artificially shift it to the acidic range so that the hydrangea continues to produce pink flowers.
This includes organic materials such as
- Compost
- ripe crap
- composted leaves
Peat, on the other hand, should only be used in exceptional cases out of consideration for nature.
Heavy clay soils can be acidified very well with sulfur or sulphate. All means of artificial soil improvement must be well incorporated into the soil.
Tips & Tricks
You only have real control over the flower color if you cultivate the hydrangea in a pot. You can also place the pretty small shrub in the flower bed with the planter so that the garden soil has no influence on the color of the flowers.