Why does your Rhododendron hirsutum have yellow leaves? Diagnose the cause and fix it with our step-by-step guide.
Rhododendron hirsutum is an acid-loving species; if the soil pH rises above 5.5, iron becomes chemically unavailable to the plant. This results in interveinal chlorosis where leaves turn yellow while veins remain dark green.
Excessive moisture or poor drainage in heavy soils can lead to fungal pathogens attacking the root system. This prevents the plant from transporting nutrients, causing a general yellowing and eventual wilting of the foliage.
A lack of available nitrogen in the growing medium leads to a loss of chlorophyll throughout the leaf. In Rhododendrons, this typically manifests as a uniform paling or yellowing of older leaves first.
While hardy, R. hirsutum requires consistent moisture; prolonged dry periods cause the plant to sacrifice older leaves to conserve water. This can lead to yellowing followed by crispy, brown leaf margins.
Your plant might also be experiencing one of these issues:
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