Rhododendron catawbiense aka Catawba Rhododendron

Rhododendron catawbiense is known as Catawba rhododendron or mountain rosebay. This evergreen shrub belongs to the heath family, Ericaceae. It grows wild in the eastern United States. Its range runs from Maryland and Kentucky to Alabama and Georgia. Many stands grow in the southern Appalachian Mountains. There, it forms thickets on wooded slopes and rocky ridges. Garden plants reach 6–10 feet [1.8–3.05 metres] tall. They spread about 6–12 feet [1.8–3.66 metres] wide. RHS gives an upper size of about 13 feet [4 metres]. Rare plants reach 20 feet [6.1 metres] tall.

Several stems form a rounded or spreading crown. Dense leaves can hide the branches near ground level. Older shrubs may develop a more open shape. The gray-brown bark forms fine scales as it ages. Young stems start yellow-green, then turn brown. The leaves grow in an alternate pattern near shoot tips. Each leaf is leathery, oval to oblong, and dark green. Its upper face shines, while the lower face looks lighter. Leaves measure 0.25–0.5 feet [0.08–0.15 metres] long. Some take on a yellow-green shade in winter.

Large flower buds sit at the ends of shoots. Flowers open from April to June, depending on the site. The funnel-shaped blooms range from lavender-pink to purple. Some plants bear white flowers. Green or yellow-brown spots mark the flower throats. Groups of blooms make a bold spring display. Their nectar draws bees, butterflies, and hummingbirds. Dry seed capsules ripen in fall and split into five sections. The fruit adds little to the garden display.

Give this shrub acidic soil rich in organic matter. Keep the soil moist, but let excess water drain. Its shallow roots suffer when the soil dries out. A yearly mulch helps hold moisture and keep roots cool. Part shade suits it well, with shelter from afternoon sun. Some sources also report good sun tolerance. It prefers cool summers and protection from strong winds. Sources list USDA zones 4–8 and UK hardiness H7. It needs little pruning, and flowers form on older growth.

Use it in woodland gardens, borders, groups, or hedges. Its leaves give winter interest and cover for wildlife. Deer may browse it and cause damage. Vine weevils, lace bugs, aphids, and whiteflies can attack it. Root rot, canker, leaf spots, and mildew are possible problems. Soil with a high pH can cause leaf yellowing. Dry, sunny, windy sites can lead to moisture loss. This shrub burns readily, so avoid placing it near homes. It contains grayanotoxins and is harmful to people and pets if eaten. Do not treat it as a food plant.