Rhododendron yakushimanum Grumpy

Plant the Rhododendron yakushimanum 'Grumpy' in a semi-shaded position, protected from cold and drying winds, in a moist, humus-rich, and light soil, with a tendency towards acidity or neutrality. Like all plants of the heath family, it does not tolerate limestone soils or heavy soils saturated with water in winter. If the soil remains moist in summer, this rhododendron can also tolerate non-burning sun exposure.

Dig a hole with a volume three times larger than the pot. Soak the root ball in non-limestone water and plant the bush at the level of the collar, in a mixture composed of leaf compost, gravel or pumice, and loam. Water generously and keep the soil moist in summer. Azaleas and Rhododendrons have a shallow root system. Therefore, they are sensitive to long periods of drought. That's why it is advisable to have humus-enriched soil and to water abundantly during drought periods. Moreover, this root system is not very strong, which is why it is essential to lighten heavy soils with draining materials (gravel, pumice, clay pellets) during planting. Place a mulch of shredded pine bark at the base of the bush every spring to keep the soil cool while maintaining an acidic pH.

Maintenance consists of cutting off faded flowers in summer and removing dead branches. Azaleas and Rhododendrons can sometimes be attacked by weevils that eat the edges of leaves and rootlets, as well as the famous "rhododendron beetle" which does not often cause severe damage. Effective biological solutions are available today against weevils. Yellowing of the leaves (chlorosis) in Rhododendrons indicates poor assimilation of iron from the soil and causes premature death of the plant. While limestone is often the cause, poorly drained soil or a deeply planted root ball can also explain the phenomenon.