Rhododendron ponticum aka Rhododendron

Rhododendron ponticum, or Pontic rhododendron, is an evergreen shrub. It belongs to the heath family, Ericaceae. Its native range spans parts of Europe and Asia. Records include Spain, Portugal, southeast Bulgaria, Turkey, Lebanon, and Georgia. It also occurs in the Krasnodar region of Russia. It grows in forests of beech, spruce, and fir. Some plants grow above the tree line. It is not native to Britain or Ireland.

The shrub grows upright and forms a dense, branched crown. Garden plants reach about 8–13 feet [2.5–4 metres] tall. Their spread falls within the same range. They take about 10–20 years to reach full size. The leaves are oval, dark green, thick, and leathery. They stay on the plant through winter. This lasting cover suits hedges and screens. The RHS also lists it for banks and slopes. Plants grown as hedges can withstand hard clipping.

Purple, funnel-shaped flowers grow in clusters at the branch tips. Each cluster holds about 10–15 blooms. Chicago Botanic Garden describes the flower shade as lavender. Its records place flowering in March and April. The RHS gives the broader season as spring. Chicago also lists birds and butterflies among its wildlife visitors. Growers have used this species as rootstock for grafted plants. The rootstock may live on after the grafted plant dies.

It grows in acid soil that stays moist but drains well. The RHS lists clay, loam, and sand as suitable soils. It accepts sun, partial shade, or full shade. Chicago lists partial shade and moderate water needs. The RHS rates its UK hardiness as H6. Chicago gives USDA zones 5–8. Yet its spread makes garden use a serious concern. UK law lists it as an invasive, non-native species. Garden growing and sale remain allowed under that listing. The RHS urges careful control and safe disposal of waste. It also urges gardeners to choose other plants instead.

Pests include vine weevils, whiteflies, leafhoppers, lacebugs, scales, caterpillars, and aphids. Diseases include powdery mildew, petal blight, and bud blast. Silver leaf and honey fungus may also affect it. Eating the plant can harm both people and pets. No edible uses are known. PFAF records medicinal use for heart and circulation disorders. It warns that such use needs expert supervision.