Why does your Rhododendron rubiginosum have sudden leaf drop? Diagnose the cause and fix it with our step-by-step guide.
Oomycetes like Phytophthora species thrive in poorly drained soils, causing root decay that prevents the plant from transporting water. In Rhododendron rubiginosum, this often manifests as rapid wilting and sudden defoliation during warm periods.
As an acid-loving species that prefers consistent moisture, extreme heat or a lapse in watering causes the plant to shed leaves as a survival mechanism to reduce transpiration. Sudden temperature fluctuations can also trigger this physiological response.
If the root ball was planted too deep or if the roots were exposed to air during transplanting, the fine feeder roots may have died. This leads to an inability to support the canopy, resulting in rapid leaf drop.
While primarily known for leaf distortions, severe fungal infections can weaken the plant's vascular system and trigger premature abscission. This is more common in high-humidity environments with poor air circulation.
Your plant might also be experiencing one of these issues:
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