What Is the Greek Rhododendron?

Rhododendron Facts

• Rhododendrons grow in U.S. Department of Agriculture plant hardiness zones 4 through 9. They are part of the heath family, related to heathers, laurels and blueberries. All parts of the shrub are toxic and should not be eaten. There are over 1,000 species of rhododendron to choose from, with bloom colors like pink, purple, white, red, orange and yellow. The shrubs grow well in humid climates with mild temperatures, and are often found growing on mountains in the wild.

Planting

• Soil should be well-draining and acidic, with a pH between 5.0 and 5.5. If you have poor soil it also needs to be amended with compost. Shrubs should be spaced about 4 to 6 feet apart unless you are planting a dwarf or small variety. The planting location should be partially shaded and sheltered from wind. Dig the planting hole just deep enough for the roots, so the plant sits at the same soil level it was in the container.

Care

• Provide the shallow-rooted rhododendron with a 2- to 3-inch layer of mulch to help preserve soil moisture. The shrubs benefit from a spring application of acid-loving plant fertilizer with lower nutrient levels, such as a 6-10-4 ratio. Water just enough to keep soil moist, about 1 inch per week, and do not let the top inch of soil dry out. No pruning is necessary for rhododendrons, but you should deadhead spent blooms.

Problems

• Root rot can be a problem if the shrubs are planted in soil that does not have good drainage. Allowing the plant to go into winter without watering properly can result in leaf scorch, especially if there is not enough shade or wind protection. Yellowing leaves with green veins indicates an iron deficiency, which can be corrected with iron sulfate. Insects are not a large problem, but if leaves appear to be eaten, check the undersides for signs of insects such as aphids. Aphids will appear as tiny moving specks and can be treated with pressured water sprays or insecticidal soaps.