Catawba Rhododendron

Size, growth and what to expect

It grows slowly, about a foot a year in our growth estimator. In gardens it reaches 6 to 10 feet and spreads 8 to 12, often wider than tall. Some plants reach 20 feet.

Trusses of 15 to 20 lilac-purple flowers, marked green to yellow-brown in the throat, open from April to June. Each flower is about 2.5 inches across. The capsules show from July to October and ripen in fall. Its thickets give birds shelter and nesting sites.

It grows wild from Virginia, West Virginia and Kentucky south to Georgia and Alabama. Its home is rocky slopes, ridges and balds up to about 6,500 feet. It has also escaped from gardens in Connecticut and Massachusetts.

How to grow Catawba Rhododendron

Catawba rhododendron does best in part shade, with morning sun and shelter from hot afternoon sun and winter wind. It takes nearly full shade, and where summers are cool it grows in full sun. It wants an acid, moist soil rich in organic matter that drains well, and it rots in wet clay. Keep it away from walnuts, butternuts, pecans and hickories. Their roots release juglone, which harms rhododendrons. Set plants 8 feet apart and keep them 6 feet from a wall. At its size it can go within 15 feet of overhead wires.

Saplings ship potted. Plant dormant plants in early spring or fall, in a hole three times as wide as the root ball and no deeper. Set the top of the ball a touch above grade, and put the native soil back in. Mulch every year with pine needles or wood chips, kept off the stems, and never dig over the shallow roots. The seed is dust-fine and needs light, with no chilling. Sow it in winter on the surface of damp milled sphagnum, uncovered, at room temperature under lights and a clear cover. Most seedlings come up within about two weeks.

Water weekly through the first two summers, and never let the soil dry out completely. Deer damage it often, so cage it where deer are common. It flowers on the previous year's wood, so prune only right after bloom.

Each flower carries both male and female parts, and bees, butterflies and hummingbirds come to the flowers. Black vine weevils, lace bugs and root rot can trouble it, and yellow leaves mean the soil is not acid enough. It is highly flammable, so keep it out of the defensible space around a house. Every part of the plant is poisonous if eaten, and honey from its flowers may be too.