Sweet Azalea

Size, growth and what to expect

Sweet azalea grows fast for a native azalea. Our growth estimator treats it as fast, about 2.75 feet a year, slowing as it nears full size. It usually grows 8 to 12 feet tall and as wide, sometimes 20 feet tall.

Clusters of 3 to 7 white or pale pink flowers open from May to July. Each is up to 2 inches across, with a red style and long red stamens. The egg-shaped capsules, about 3/4 inch long, follow from July to October. The leaves turn red to purple in fall.

It grows wild in the Appalachians from Pennsylvania and Kentucky south to Georgia and Alabama. Its home is stream banks, rocky streamsides, heath balds, swampy woods and bogs, from about 300 to 4,900 feet.

How to grow Sweet Azalea

Sweet azalea does best in part shade or dappled light, in moist, acid, sandy or loamy soil that drains well. It takes ground that is wet for short spells and suits a rain garden, but the roots must not stand in water. Full sun can scorch the leaves, and it does poorly where summers are hot. 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 little above grade, and put the native soil back in. On heavy clay, plant on a raised bed or choose another spot. Mulch with wood chips, bark or pine needles, kept off the stems. 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. Seedlings come up in one to three weeks.

Water weekly through the first two summers, since it is sensitive to drought and the shallow roots must never dry out. Never hoe or dig over them. Rabbits leave it alone, but deer damage it often, so cage it where deer are common. Prune, if at all, right after bloom, since next year's flower buds form by mid to late summer.

Each flower carries both male and female parts, and bees, butterflies and hummingbirds visit the flowers. Sources disagree on whether a native azalea sets seed with its own pollen, so plant two seedlings from different parents for seed. It sometimes crosses with swamp azalea, and seed from a plant near other azaleas in bloom may give hybrids. Lace bugs, aphids and mites can mark the leaves, and root rot follows poor drainage. Every part of the plant is poisonous if eaten, and honey from its flowers can be too.