Rhododendrons, from the Ericaceae family, are native to Asia, Europe, North America and Australia. They are most appreciated today for their beautiful flowers. They have been cultivated in Europe and Asia since 1600. The Native Americans harvested the leaves to treat inflammation. Herbalists still commonly use the leaves in compresses for the same reason. These beautiful shade-loving flowering shrubs are cultivated and appreciated all over the world. There are literally hundreds of different species. They are grown in different ways, but they are easy to grow in flowering hedges, planted along the edge of a garden as a border or in containers!
Types of rhododendrons
The main categories of rhododendrons are evergreen rhododendron shrubs, deciduous rhododendron shrubs and rhododendron trees (also evergreen). Azaleas are a specific variety of rhododendrons, but are different enough from the main family to have their own rules of care. Evergreen rhododendrons are a good way to preserve patches of greenery in your garden during the winter. Deciduous varieties will lose their leaves in winter, but both types are perennials and will return in full force in spring.
Rhododendrons
Perennial
Partial shade in full sun
Moist, well-drained acidic soil (pH 4.5-6.0).
Start seedlings or cuttings indoors in after autumn.
Plant in the garden 2 weeks after the last frost in spring.
Plant 48″ apart for healthy shrubs.
Growing in containers:
Start individual plants in pots at least 12″ deep and 16″ wide
The pot should be as wide as the foliage, switch to a larger pot as it grows
Ensure good drainage and acidic soil
Water regularly, keeping the soil moist.
Climatic zones 6-9 for evergreen varieties
Climatic zones 4-9 for deciduous varieties
How to plant rhododendrons
Plant rhododendrons in the spring after the last frost or in early autumn. The plants begin their dormancy in the fall and come out of their dormant phase in the spring. In colder climates, plant rhododendrons in the spring. An autumn planting will still work in many matters, especially if precautions are taken, but young plants are sensitive to winter frosts. In heat up climates, autumn planting is preferable. The distance between each plant should be about four feet (48 inches), unless the variety you are planting is much larger or smaller than that. Plant them in a hole about as deep as the roots, and about twice as wide, and fill them with healthy organic soil, with a little compost. For climates that are between hot and cold, planting at any time of the year can work, but spring is probably still the best.
The location of the plant in relation to the sun, the ground and sheltered from the wind are some of the most important factors in deciding where to plant rhododendrons. Herbaceous rhododendrons with larger leaves especially need sun for part of the day and shade for the rest of the day, or dappled sun throughout the day. Evergreen rhododendrons can tolerate more sun but also prefer partial shade. If you can, plant on the north side of a structure (such as your house or outbuilding) so that they have shade for part of the day, especially in heat up climates.
The soil should be a little acidic, rhododendron does not do well in alkaline soils. Good drainage is necessary and the soil must be rich and fertile. If there is a lot of clay soil, it is better to dig around the base of the plant when planting, add more clay soil or modify the soil to facilitate drainage. Make sure that these shallow-rooted plants are planted close to the surface and have moist soil, neither too dry nor too wet. In areas that receive a lot of wind in winter or if a storm is expected in any season, it is preferable to create a shelter, or a windbreak, around the plant, to avoid wind damage.
These beautiful flowering shrubs are really easy to grow, the main things to remember are: make sure that the soil drains well and is not too wet, plant them where they have light and shade, and use straw or shredded bark as mulch in winter to protect the shallow roots from the cold!
Growing rhododendrons in containers
They do very well in the garden, but they are also excellent in containers. Due to their superficial root system, they are suitable for containers, just take care that the pot is wide enough. The final pot should be as wide as the full-growing plant. It is quite easy to transplant small rhododendrons, so it is normal to start them in small pots and move them to larger pots. The containers allow great control over the type of soil and the available light. The right pot will also help to ensure good drainage!
