If the foliage of the hydrangea turns yellow, the plant is usually missing important nutrients. We explain to you which causes are responsible and how you can quickly remedy the situation.
Yellow leaves on the hydrangea indicate a lack of nutrients
nitrogen deficiency
If there is a lack of nitrogen, the entire leaf usually turns yellow. At first, only the older leaves in the lower part of the hydrangea are affected, and only later do the leaves that have been pushed along change color. The flowers can also wither as a result.
remedy
Fertilize the hydrangea with a nitrogen fertilizer from a garden store. Please note 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 favored 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 foliage turns yellow.
- Brown necroses form from the edge of the leaf.
- The stems become thinner.
- The roots shorten and show an unhealthy brown coloration.
remedy
Always fertilize the hydrangea with a special fertilizer containing iron. If there is still an iron deficiency, you can use a pure iron fertilizer.
danger
Iron fertilizer is toxic, so be sure to wear protective clothing when applying.
soil pH
For red hydrangeas to retain their vibrant flower color, the soil needs to have a relatively high pH level. This can lead to the plant no longer being able to absorb enough iron. If yellow leaves appear on a red hydrangea, you should therefore correct the pH value. Organic fertilizers such as compost are well suited.
tips and tricks
Foliage turning yellow in the fall is normal due to the natural growing cycle. The hydrangea is one of the deciduous plants in which the leaves first turn yellow in autumn and then fall off on their own.