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Description
Rhododendron Maximum, commonly known as the Great Laurel or Rosebay, is a species of Rhododendron native to the eastern United States. This evergreen shrub can grow up to 30 feet tall and 20 feet wide, making it an impressive addition to any landscape. It produces large clusters of showy white or pink flowers in the late spring to early summer, with dark green leaves that remain on the plant year-round.
Taxonomic Information
| Domain | Eukaryota |
| Kingdom | Plantae |
| Phylum | Tracheophyta |
| Class | Magnoliopsida |
| Order | Ericales |
| Family | Ericaceae |
| Genus | Rhododendron |
Appearance
Rhododendron Maximum has a dense, upright growth habit with a rounded shape. Its large, glossy leaves are elliptical in shape, measuring up to 8 inches long and 4 inches wide. The leaves are dark green on the top surface and paler on the underside. The plant produces large clusters of trumpet-shaped flowers that can be white or pink, with a yellowish-green throat. The flowers are about 2 inches wide and are produced in late spring or early summer.
Care Guide
Rhododendron Maximum prefers well-draining, acidic soil with a pH between 4.5 and 6.0. It also requires adequate moisture, so it’s important to keep the soil evenly moist, but not waterlogged. Fertilize the plant in the spring with a slow-release, acidic fertilizer. This shrub likes partial shade to full sun exposure and is hardy in USDA Zones 4-8. Prune the plant after flowering to maintain a compact shape and remove any dead or damaged branches.
Common Pests & Diseases
Rhododendron Maximum is susceptible to several pests and diseases, including lace bugs, spider mites, and root rot. Lace bugs and spider mites can be controlled with insecticidal soap or neem oil, while root rot can be prevented by planting in well-draining soil and avoiding overwatering. This plant is also prone to fungal diseases such as powdery mildew and leaf spot, which can be treated with fungicides.
Habitat
Rhododendron Maximum is native to the eastern United States, where it grows in moist, acidic soils in woodland areas and along stream banks. It is commonly found in the Appalachian Mountains and the Piedmont region.
Question and Answer
Q: Can Rhododendron Maximum be grown in containers?
A: While it’s possible to grow Rhododendron Maximum in containers, the plant will eventually outgrow the pot and will need to be transplanted into the ground.
Q: How often should Rhododendron Maximum be fertilized?
A: Fertilize Rhododendron Maximum once a year in the spring with a slow-release, acidic fertilizer.
Q: What is the best time of year to prune Rhododendron Maximum?
A: Prune Rhododendron Maximum after flowering in the late spring or early summer.
Q: Can Rhododendron Maximum tolerate full sun exposure?
A: Rhododendron Maximum prefers partial shade to full sun exposure.
Related Plants
- Rhododendron catawbiense
- Rhododendron ponticum
- Rhododendron yakushimanum
- Rhododendron ‘Nova Zembla’
References
- “Rhododendron Maximum.” Missouri Botanical Garden. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b745
- “Rhododendron Maximum.” Plant Database. University of Connecticut. https://www.hort.uconn.edu/plants/detail.php?pid=431
- “Rhododendron Maximum.” Royal Horticultural Society. https://www.rhs.org.uk/Plants/19414/Rhododendron-maximum/Details
