Rhododendron enthusiasts who have no garden need not abandon their ambition to grow their own plants. Many of these colourful shrubs can be grown in pots, large containers or tubs.
The nursery here is in an old kitchen garden, where the soil has been change over the years to alkaline by adding chalk. Vegetables prefer an alkaline soil None of the plants can be grow in the ground so remember if you don't purchase them we carry on growing them, potting them up into larger and larger pots. We have some plants in tubs you could bath in.
Rhododendrons and azaleas are flat-rooting plants and will require broad, shallow containers rather than deep ones. Depending on their rate of growth, 30-40-cm (12-16 in) deep containers, with a diameter of 60-100 cm (24-40 in), may be sufficient. Japanese azaleas and dwarf rhododendrons will even flourish in large balcony boxes.
Rhododendrons require humus-rich, acid soil of a loose consistency in their pots or containers, just as they would in the garden. The ideal soil can be mixed out of commercially produced rhododendron soil (ask at your garden centre etc.) with coarse sand in a ratio of 5:1, or you can make up your own soil using leaf mould or lime-free composting soil, peat and coarse sand in a ratio of 2:2:1. No matter which soil mixture you decide on, it should always have some basic fertilizer mixed in with it. A mineral controlled-release fertilizer is very suitable (ask at your garden centre etc. for a good brand) as it will gradually release the nutrients over a period of six months.
Good drainage is essential so you must make sure some form of drainage is present to help surplus water to run away. Check the container has drainage holes in the bottom. Fill the bottom of the plant container with a 5cm (2 in) layer of coarse gravel or sand and cover it with a piece of interfacing material so that the drainage layer does not become clogged up with soil and the drainage holes blocked. Then fill the pot up with soil.
Early spring and early autumn are equally suitable times. Planting in spring has the advantage that you will not have to wait so long before enjoying the flowers. My experience, however, is that shrubs planted in the autumn seem to root faster and better.