Hydrangea yellow leaves are beautiful, flowering shrubs that produce huge blooms in summer. But sometimes they turn yellow with crispy, blotchy leaves and other symptoms that can indicate disease or pest infestation. The good news is that most of these problems are preventable with proper soil management, such as the addition of drainage elements to clay soils and regular fertilization of nutrient-rich complex mineral plant feeds.
Hydrangea yellow leaves are most often caused by nutrient deficiency, especially iron and magnesium deficiencies. If the hydrangea leaves are yellow between the veins but the veins themselves are green, this is called chlorosis and indicates a magnesium deficiency. Treat this by adding a magnesium sulfate fertilizer, such as Epsom salt, to the soil around the hydrangea. A magnesium deficiency may also be a result of high alkaline soil pH levels, which can be corrected by applying an acidifier to the soil, such as horticultural vinegar or citrus juice.
Golden Troubles: Diagnosing and Treating Yellow Leaves on Hydrangea Plants”
Another common cause of hydrangea yellow leaves is poor drainage, which causes the roots to become soggy. This can be corrected by improving the soil condition, such as adding draining elements to clay soils or working in sand for better soil drainage, or by watering less frequently.
Lastly, if the leaves of a hydrangea are turning yellow with blotchy blotches, this is a sign of fungal or bacterial disease, such as nematodes or tomato ringspot virus (TRTSV). To protect your hydrangeas from disease, keep the soil as dry as possible and don’t disturb the root ball when transplanting. Also, sanitize tools before and after working with your hydrangea to prevent the spread of pathogenic spores.