Why does your Hydrangea arborescens have yellow leaves? Diagnose the cause and fix it with our step-by-step guide.
In Smooth Hydrangeas, a lack of nitrogen often manifests as chlorosis, where older leaves turn pale yellow while the veins may remain green. This is common in heavy-feeding species like H. arborescens when soil nutrients are depleted by high summer growth.
Hydrangeas require consistent moisture, but waterlogged soil deprives the roots of oxygen. This leads to yellowing foliage as the root system begins to fail due to lack of respiration.
If the soil pH is too high (alkaline), the plant cannot uptake iron. This results in bright yellow leaves with distinct dark green veins, a common issue in certain garden soils.
While they love moisture, extreme dry spells can cause leaves to yellow and eventually crisp at the edges. This is often a rapid response to high heat and low humidity during summer months.
Your plant might also be experiencing one of these issues:
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