Rhododendron maximum, commonly called rosebay rhododendron or great laurel, is a large, upright, loose, multi-stemmed, late-blooming, evergreen shrub that is native to North America from Ontario and Nova Scotia south to Ohio, Alabama and Georgia with a concentration of plants in the southern Appalachian Mountains where it typically grows in dense thickets which dominate the understory in some locations. It typically grows to 5-15’ tall, but infrequently to 30-40’ tall in the heart of its native habitat. Large, leathery, strap-like, evergreen leaves (typically to 4-8” long) have undersides with a hint of rusty orange. Flowers (to 2” across) are rose-purplish to pink to white, often with olive green to orange spots. Flowers bloom in umbel-like inflorescences from June to early July. Fruit is an oblong seed capsule which splits open when ripe to release numerous seed. Winter hardy to USDA Zones 3-7 where it is best grown in acidic, humusy, organically rich, cool, moist, moisture-retentive but well-drained soils in part shade. Tolerates close to full shade. All parts of this plant are highly toxic if ingested. Shrub borders. Shady locations. Naturalistic areas. Wood margins.
Growing Instructions for the Rosebay Rhododendron
The seeds like moist, well-drained soil. 1. Fill a container with sterile soil or a sterile seed starter mix. 2. Sow the seeds on the surface of the soil. The seeds need light to germinate. 3. Water the soil so that it is moist but not wet. The seeds take 10 to 20 days to germinate. 4. When the seedlings are a few inches tall, they can be transplanted.