Rhododendron simsii Clotilde - Knaphill Azalea

Rhododendron or Azalea Clotilde is a very rare historical, cultivated variety, occasionally found in arboretums or specialised collections. It is a semi-evergreen to evergreen plant depending on the climate, and shows little resistance to frost, suffering from around -7°C. It slowly grows to form a relatively compact clump, with a somewhat spreading habit, wider than it is tall. From April, depending on the region, it produces clusters of trumpet-shaped flowers, in a delicate light pink punctuated with a yellow spot. It can only be planted out in mild climates and acidic soils. It should be grown in a pot to be brought indoors in winter when these conditions cannot be met.

Azaleas, which from a botanical point of view are actually Rhododendrons, belong to the Ericaceae family, much appreciated in gardens for their many ornamental genera. It notably includes all heathers (Erica, Calluna, Daboecia...), the Strawberry Tree with both decorative and edible fruits, the charming little Leucothoe, Kalmias (mountain laurels) etc. There are over a thousand wild species of Rhododendrons, distributed in temperate regions, but also in the tropics (the vireya group) and in intermediate climatic zones, such as Rhododendron simsii. It grows naturally in southern China and the northern half of Southeast Asia. It is the main parent of Indian Azaleas, a horticultural designation that groups hybrids often obtained in Belgium. This is the case for 'Clotilde', which is the result of the work of breeder Alexander Verschaffelt in Ghent in 1851. This specialist gave rise to dozens of other varieties, many of which have since fallen into obscurity.
The 'Clotilde' Azalea is a small bush with rather slow growth, which after 10 years of planting reaches roughly 70 cm in height with a spread of 1 m. Depending on the climate, it may eventually grow to 1.50 m tall, without ever becoming truly invasive, allowing it to be planted even in a small border. It can also be grown in a pot in cold regions whose winters it will not tolerate due to its limited hardiness (-7°C to -9°C). Belgian horticulturists sometimes force this type of plant, bringing them into warm shelter to make them flower earlier, i.e., in winter. Outdoors, the plant usually flowers in April or May. The dark green foliage is semi-evergreen to evergreen, depending on the climate, formed of small elliptical leaves with a pointed tip measuring 3 to 6 cm long. This vegetation sets off the light flowering well, which blooms in clusters of 5 to 12 flowers or more, at the ends of shoots. The corollas consist of five petals fused at the base (these are called gamopetalous flowers)  whose ends open into a trumpet shape. They are a light pink, sometimes deeper, with slightly darker areas here and there; one of the petals has a yellow dominance, which gives a small, very aesthetic variegated appearance.

At home in an oceanic climate, such as that of the southwest, the 'Clotilde' Azalea should be planted under protective shade in Mediterranean areas, and always in acidic soil. It will thrive with other ericaceous plants, like Japanese Andromedas (Pieris) with their very decorative foliage and flowering. In regions where the winter is too cold or the soil unsuitable, you can grow it in a container to adorn a shaded terrace in summer, alongside other plants like charming Skimmias or plants with a more exotic appearance, such as citrus trees.