Rhododendron are highly valued in landscaping. Their gorgeous pink flowers brighten up any location. The flowers also attract bees and the rare bog elfin butterfly (Callophrys lanoraieensis) that drinks its nectar after hatching. They are a remarkable flower because of their explosive, butterfly-like look.
Where to Plant
In nature, find rhododendron in acid soils and peat bogs. It is great plant for beds and borders, bog garden, cottage and informal gardens, waterside, and woodland gardens.
Rhododendrons often have shallow roots. As a result, they are susceptible to competition from other plants and should be placed far from trees that give shade. You want it to be in the sun for at least portion of the day, ideally in the morning. And never place a rhododendron in direct sunlight.
Gardeners commonly reproduce rhododendrons using stem cuttings, seeds, grafting, and micropropagation. Rhododendrons often generate hundreds of small seeds in their capsules, which are distributed by wind after the fruits break in the autumn. Seeds lose viability quickly, but may be stored dry and cold for a long time.
Rhododendron cultivars are mostly propagated by cuttings. Plants sold locally are the most appropriate cultivars for the locality. Be careful of large marketers distributing mass-produced biotypes. It is advisable to search for recently bred attractive cultivars bred in the local climate.
To plant a rhododendron acquired in a container, remove the root ball from the container. If dry, soak until thoroughly moist. If pot-bound, score and loosen the fibrous roots. Plant in porous loam soils rich in organic matter. Good drainage is essential. Place top of root ball slightly higher than the top of the hole, meaning higher than surrounding ground surface. Firm-in soil around root ball. Water-in well. If a site has clay or alkaline soil, consider raised beds.
Applying a few inches of organic mulch annually helps maintain soil moisture and suppress weeds.
Caring for Rhododendron
Grow in moist, humus-rich, cool, acid soil in full sun or partial shade. Mulch in spring to maintain soil moisture. Do not allow roots to dry out. Watering should be done only when the soil is moderately dry, but plants should not be subjected to drought. Protect from cold, drying winds. They should be protected from harsh winter conditions.
There are differing views on best practices for growing rhododendrons. Hundreds of articles are available online at the website of the American Rhododendron Society, experts offering opinions ranging from benign neglect to sophisticated analyses of fertilization, pruning, landscaping, and other topics.
Pruning is not essential. Nonetheless, deadheading after flowering is not uncommon. And like many plants, diseased and damaged branches should be removed.
All parts of the plant are toxic to dogs and cats and other animals. Susceptible to numerous pests and diseases. Rhododendrons tolerate rabbits, but deer frequently damage.
Despite the toxic properties, rhododendron species have been widely used in folk medicine systems in Asia, Europe, and North America. These plants have been effective against many medical conditions including gastrointestinal problems, inflammation, pain, skin problems, and the common cold. Rhododendrum groenlandicum has even been used by North American indigenous people to treat diabetes.
Because of their attractiveness, rhododendron species have frequently been chosen as official emblems of political regions. For example, it is the state flower of West Virginia adn Washngton State. It is also the national flower of Nepal.