hello, my problem is: I have 2 pink rhododendrons elegans, which until last year were beautiful and lots of flowers. This year they started with brown leaves, then they dry out and fall off. then near the buds the new leaves curl up a bit
rhododendrons are shrubs of Asian origin, those that are generally grown in the garden, even if there are European species and also present in nature in Italy. Since your plants were well, they may have contracted some disease, but from the description of the symptoms, rather leaning towards the hypothesis that not completely correct treatments, which continued over time, favored the development of parasites. In your case I think it is root rot, which 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 love cool and humid climates, and therefore the soil tends to be often left saturated with water. Unfortunately, this condition is not healthy for the roots, which tend to suffocate and are easily attacked by fungi. Rhododendrons need regular watering but do not like a soil always soaked with water; therefore with the arrival of spring and increasing temperatures, the watering must be more frequent, always waiting for the soil to dry between two waterings. Since you grow your rhododendrons in pots, perhaps in autumn it would be advisable to repot them, replacing all the soil with fresh potting soil, mixed with a little sand, so that it can become difficult for the water to create stagnations. Every 10-12 days, throughout the summer, supply a specific fertilizer for acidophilic plants. If you don't see any improvements over the weeks, changing the watering frequency, try to administer a systemic fungicide, that is to be supplied in the water, so that it remains in circulation for a long time in the whole plant.