Rhododendron Irene Koster

The 'Irene Koster' Azalea should be planted early in autumn in a light, moist, and acidic soil. In a limestone soil, create a large pocket of pure peat soil. Dig a hole measuring 50cm (20in) in all directions, lay down a geotextile film, and fill it with peat soil. This process prevents the peat soil from mixing with your garden soil. Mulch the soil with maritime pine bark and water generously. Always keep the soil moist, especially in summer. Fertilize in spring with a rhododendron fertilizer. Pruning is unnecessary. Remove faded flowers to promote the emergence of new shoots. The Azalea has few diseases when well established outdoors. It may be attacked by weevils that eat the edges of the leaves and rootlets, as well as by the famous "rhododendron beetle," which rarely causes damage. If this is the case, treat it with carbofuran. If the soil is limestone, if the plant is planted too deep, or if the soil is poorly drained, the leaves may turn yellow.