good morning, my problem is: I have 2 pink rhododendrons elegans, which until last year were beautiful and many flowers. that year they started with brown leaves, then they dry up and fall. then near the buds the new leaves curl up a little
rhododendrons are shrubs of Asian origin, those that are generally grown in the garden, although there are European species and also naturally occurring in Italy. Since your plants were doing well, they might have contracted some disease, but from the description of the symptoms, I rather prefer the hypothesis that not completely correct cures, which lasted over time, favored the development of parasites. In your case I think it is root rot, which has consequently also caused the drying of leaves and perhaps even small twigs. It is not uncommon for these pests to develop between the roots of rhododendrons, as they are plants that like cool, wet climates, and therefore the soil tends to be left often saturated with water. Unfortunately this condition is not healthy for the roots, which tend to suffocate and come easily attacked by the mushrooms. The rhododendrons need regular watering but do not like a soil always soaked with water; therefore with the arrival of the spring and the increase of the temperatures, the waterings must several more frequent, always waiting for the ground to dry between two waterings. Since you grow your rhododendrons in pots, perhaps in autumn it would be appropriate to repot them, replacing all the soil with fresh soil for acidophilic, mixed with little sand, so that it can become difficult for water to create stagnation. Every 10-12 days, throughout the summer, provide a specific fertilizer for acidophilus. If during the weeks, changing the frequency of watering, you do not see improvements, try to administer a systemic fungicide, that is to say that it must be supplied in the water of the watering, so that it remains in circulation for a long time in the whole plant.