Hortensias are among the very robust flowering plants that cope well with a wide variety of locations. In order for the hydrangea to produce many flowers and retain its original flower color, the substrate must be tailored to the special needs of this garden beauty.
What soil do hydrangeas need?
For hydrangeas, a nutrient-rich, deep, humus-rich and acidic soil with a pH value of 4 to 4.5 is ideal. Special hydrangea soil or rhododendron soil are suitable for this. Make sure there is a sufficient supply of trace elements and suitable soil conditions depending on the flower color.
Demands on soil conditions
The hydrangea prefers a nutrient-rich, deep, humus-rich and acidic soil. A low lime content is tolerated by most varieties. So that the plants thrive right from the start, it is important to prepare the substrate accordingly.
Hydrangea soil, a very special soil
The easiest way to create the optimal conditions is to plant in special hydrangea soil. This substrate has a pH value of 4 to 4.5 and is enriched with all the trace elements that the hydrangea needs to grow. Alternatively, you can use rhododendron soil, which has roughly the same composition.
Mix your own soil
If you want to create an entire border with attractive flowering plants, you will need a relatively large amount of expensive substrate. Instead, mix hydrangea soil yourself. This also has the advantage that you can optimally match the substrate to the flower color.
Acidify soils
If the pH value of the soil is significantly above 5, you should add acidifying agents to blue and pink flowering hydrangeas. Sand or peat quickly lower the pH value, although for ecological reasons you should only use peat in exceptional cases. Instead, mix in rotted leaves, chopped wood or grape pomace. Moisten the substrate and wait a week before measuring the pH again. If this is still too high, mix in a little more of the acidifying agents.
Blue hydrangeas, which thrive in this acidic soil, also require hydrangea blue doses twice a year.
Move acidic soils to the alkaline range
Red and pink hydrangeas only retain their bright flower color in alkaline soils with a pH value of at least 7. If this value falls below, the flowers gradually turn pink.
If the soil is loose, deep and able to store enough water, it is sufficient to lime the acidic substrate at regular intervals. Since hydrangeas often show a lack of iron in alkaline soils, you should use a fertilizer that contains this trace element.
Tips & Tricks
In order to estimate whether you need special soil, we recommend that you first carry out a soil analysis. You can obtain test sticks from specialist retailers. Alternatively, you can have a laboratory carry out a thorough soil analysis, which also provides information about the trace elements present in the soil.