There are so many different, varying in height from ground cover to trees, some with minute and some with very large , with an equally wide range in flower sizes, forms and colours and a flowering season from January to July, that it would be possible to stock a garden with this remarkable genus alone and still have plenty of variety. All kinds thrive best in rather acid soils and are not happy on chalk or limestone unless regularly fed with specially formulated iron and manganese.
Most succeed best in soil that contains plenty of peat or leafmould so that it retains moisture well in summer without becoming waterlogged in winter, and most also like to grow in the dappled shade provided by fairly widely spaced trees. However, the varieties collectively known as Hardy Hybrids, all of which make fairly big evergreen bushes carryingin May and June in dome-shaped clusters, are extremely adaptable and will succeed quite well in full sun. They are also the best for town gardens since they put up with a chemically polluted atmosphere better than most of the species and pedigree hybrids.
transplant well and can be moved in autumn or late winter, even when quite large, which makes them specially useful where quick results are essential. They will submit to quite hard in spring, but this results in the loss of at least one year’s flowering.
Varieties are so numerous that it is impossible to do justice to them in any short list. Because they transplant so readily and are usually available either balled or in containers, there is much to be said for purchasing them in flower, but since most start to flower while still very young, the size of nursery plants does not give any indication of ultimate dimensions which should therefore be ascertained.
In terms of size, the vast range of rhododendrons available from garden centres and nurseries ensures that everyone has an opportunity to enjoy these beautiful. The smallest will adorn a window box, there are many suitable for tubs, and the largest will need a woodland site to spread themselves.
Nearly all rhododendrons are evergreen and belong to the ericaceous family, which includes azaleas and heathers. This whole family has one particular requirement – the soil must be acid. This means that no quantity of lime should be present. Planted into the wrong soil your’s leaves will look yellow and sad. But do not despair if you have alkaline soil. It is quite rhododendrons in and tubs using an acid and with soft rainwater.
If you have a cool green-house or conservatory from which you can exclude the frost, this will allow you to grow the most exquisite range of fragrant rhododendrons.
Since many rhododendrons originate from the high, often snow-covered hills of the Himalayas, they are fairly used to occasional cold winters and can generally be described as quite hardy. However, there are a few very early spring varieties and the beautiful flowers of these are sometimes damaged by the frost. Try to find a well sheltered site for such plants, perhaps tucked under the shade of a suitable tree or shrub to give protection from frost and cold dry winds.
These give you wonderful colour and scent during the first days of early spring. Like all your rhododendrons, theones require exactly the same acid, lime-free . After flowering they can be plunged, with their , into the garden, provided you are sure the soil is not alkaline. However, remember to bring them back indoors before the first frost of autumn.
A wide choice
Across many regions of Britain the largeponti -cum has become naturalized in woods and on open moorlands, producing a mass of deep purple in late spring and early summer. This lovely plant was introduced into the country from Turkey about 200 years ago. Unfortunately, it has been almost too successful in spreading from , and foresters are liable to look upon it as quite a serious weed. However, in the garden it remains useful because it offers you a quick-growing plant that will form an excellent, hardy evergreen hedge or high screen that will flower profusely in late spring. Equally effective as hedges and screens are ‘Cunningham’s White’ and the brilliant scarlet ‘Britannia’.
Many smaller species naturally occur at quite high altitudes on open mountain sides, some as high as 3,600m/12,000ft. These and their hybrids can be quite truthfully described as al- pines. They offer us a wide selection of low-growing plants that will tolerate full sun and thrive in cool, moist conditions. All these dwarf plants can be put to great use in a | small garden and can be equally effective in a rock garden or raised bed provided the soil is suitable. Maximum interest and colthroughout the year is our what everyone would like to achieve in the garden. However, because rhododendrons have a limited flowering season, careful thought must be given to suitable companion planting for them.