If you love a romantic bed design, in which the flowers of the plants captivate with harmonious colors one year and set colorful color contrasts the next year, you are spot on with hydrangeas. The relatively low-maintenance hydrangea usually flowers pink by nature, but depending on the soil, the flowers can change color to purple, blue or red. In order for the pure flower color to be preserved, some care measures may be necessary.
Pink becomes blue
It is not unusual and what makes this plant particularly appealing is that many hydrangeas have different colored umbels of flowers and that the individual flowers are sometimes even multicolored.
The pH value of the soil and the aluminum content of the earth are responsible for the different colors. Only when this value is around 6 does the hydrangea adorn itself with pink umbels of flowers. 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 above 7, the tint often changes to a rich red.
Preserve the original color
So that the hydrangea does not undesirably change color and its delicate flower color is retained, you must ensure that the soil has a pH value of around 6. You can use test sticks to analyze for yourself whether the soil in your garden is more acidic or alkaline.
If you need to raise the pH value a little, you can deacidify soil that is too acidic by regularly applying lime.
On the other hand, if your garden soil has an alkaline pH value of more than 6.5, you can artificially shift it to the acidic range so that the hydrangea continues to produce pink flowers.
For this purpose, organic materials such as
- compost
- ripe crap
- composted foliage
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 iron sulphate. All means of artificial soil improvement must be worked well into the soil.
tips and 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 does not affect the color of the flowers.