Green gardening: growing rhododendrons and azaleas

The vivid displays produced by rhododendrons and azaleas can last from spring into summer. There are plants to fit any size garden, but the soil must be right. Here's a guide to growing them:

Where they can be grown, rhododendrons and azaleas make excellent additions to the home landscape.

• Ranging from mat-like dwarf shrubs no more than a few centimetres/inches high to trees more than 12 metres (40 feet) tall, these plants offer a remarkable variety of sizes and shapes.
• Most rhododendrons have magnificent foliage, and the flowers of many varieties are among the most beautiful in the world of shrubs. Flower colours are white, lavender, violet, purple, pink, crimson, scarlet, orange, and yellow.
• Varying in size from two to 15 centimetres (one to six inches) wide and from two to 10 centimetres (one to four inches) long, flowers can be tubular, starry, funnel- or bowl-shaped, and bell-like.
• They are usually produced in rounded trusses with as many as 15 individual blossoms on each one.

Rhododendrons and azaleas grow beautifully in dappled sunlight or partial shade and in moist, acid soil.

• They also do quite well in full sunlight, although flowers will last longer with some shade.
• They will not survive in alkaline soil or in hot, dry situations.
• Rhododendrons and azaleas have a remarkable range of hardiness.
• Gardeners in all but the coldest climates can enjoy at least a few of these attractive shrubs.

The word "rhododendron" is derived from the Greek words rhodon ("rose") and dendron ("tree").

• When the traditional large-leaved rhododendrons are in bloom, they fully live up to the promise of their name.
• The first species made available for garden use, in the mid-1600s, was Rhododendron hirsutum, native to the mountains of Europe.
• In 1753 the Swedish botanist Linnaeus officially established and named the genus Rhododendron. At the same time he created the separate genus Azalea.
• Then, in the 19th century, another botanist, George Don, discovered there was little botanical difference between the two, and they were both classified as the genus Rhododendron, which they remain to this day.
• Gardeners, however, still talk of rhododendrons and azaleas as separate kinds of plants, and they are so identified in nurseries and catalogues.
• There are deciduous and evergreen species of both kinds. The evergreens are the most popular, but there is an increasing interest in deciduous azaleas. Few deciduous rhododendrons are grown.

Rhododendrons occur in the wild all over the world.

• Most hybrids have been developed from species native to Burma, China, and northern India. Many of these were crossed with native North American species, particularly R. catawbiense, which grows wild in the mountains of the southern United States.
• The more resistant a rhododendron is to cold weather, the more resistant it will also be to heat. Therefore, to grow rhododendrons in a warmer climate than is usually recommended, it is best to choose the hardiest varieties.

Try growing these beautiful plants in your garden to add some colour and flair. It's an easy way to brighten up your yard!