If the foliage of the hydrangea turns yellow, the plant is usually lacking important nutrients. We will explain to you what causes are responsible and how you can quickly remedy the situation.
Why do hydrangeas get yellow leaves?
Yellow leaves on hydrangeas can be caused by nitrogen deficiency, iron deficiency (chlorosis), or unsuitable soil pH. Nitrogen fertilizers, special fertilizers containing iron or correcting the pH value with organic fertilizers such as compost can help.
Nitrogen deficiency
When there is a nitrogen deficiency, the entire leaf usually turns yellow. Initially only the older leaves in the lower area of the hydrangea are affected, only later do the new leaves also change color. As a result, the flowers can also wither.
Remedy
Fertilize the hydrangea with a nitrogen fertilizer (€8.00 on Amazon) from the garden store. Please follow the dosage stated on the package and do not over-fertilize the hydrangea. Too much nitrogen can also cause plant damage.
Chlorosis
Iron deficiency usually occurs in connection with the acidic soils preferred by the hydrangea. The younger to middle-aged leaves are affected first. They show a yellow-green to lemon-yellow discoloration. The leaf veins are sharply defined and dark green.
If iron deficiency persists, the following damage occurs:
- All the foliage turns yellow.
- Brown necrosis forms starting from the edge of the leaf.
- The stems become thinner.
- The roots shorten and show an unhe althy brown color.
Remedy
Always fertilize the hydrangea with a special fertilizer containing iron. If you still have an iron deficiency, you can use a pure iron fertilizer.
Attention
Iron fertilizer is poisonous, which is why you should definitely wear protective clothing when applying it.
Soil pH value
In order for red hydrangeas to retain their bright flower color, the soil must have a relatively high pH value. This can lead to the plant no longer being able to absorb iron in sufficient quantities. If yellow leaves appear on a red hydrangea, you should correct the pH value. Organic fertilizers such as compost are well suited.
Tips & Tricks
Foliage that turns yellow in autumn is normal due to the natural vegetation cycle. The hydrangea is one of the deciduous plants whose leaves initially turn yellow in autumn and then fall off on their own.
