Gardening: Dazzling azaleas to fill your garden with colour

Japanese azaleas were originally bred in Japan for their intense shades of bright red, pink, red-purple and cool white, and their colours have been fantastic in the last few weeks, covering the bushes, in many cases, completely so that the leaves were hidden.

These are smallish plants, broader than they are tall, and generally stay very neat and tidy, not becoming too tall, broad or straggly.

In fact, they often form flat-topped bushes that have great shape as well as colour.

The evergreen azaleas are not big plants, they rarely reach more than about chest-height and 2m across.

There is great variation among the different varieties and some kinds are bigger than others, and have different growth habit.

Some kinds are upright, some are low-growing, of more spreading habit. Like their deciduous cousins, their botanical name is rhododendron, and they need much the same conditions: good acid loam, well-drained, part-day sunshine and some shelter.

Group planting

While the evergreen azaleas can be used as single plants, they are at their most effective when planted in a group.

The group might have several different colours. They nearly all blend well together because they are closely bred.

The colours are mostly shades of red: pink, orange-pink and pink-purple as well as red. There are white varieties too, and these set off the red colours very well.

When mixing colours, it would be best to have most of the planting of the same variety, perhaps no more than two or three kinds used to provide contrast.

The different varieties all overlap in flowering period, but some start a little ahead of the rest and others finish somewhat later.

If more than one variety is used, this spreads the flowering period by at least a week at each end.

There are many varieties but some of the best known, and most available, are among the following. ‘Hatsugiri’ is smallish, tight in habit and covered with flowers of intense rose-purple.

‘Vuyk’s Scarlet’ has rich scarlet flowers and ‘Vuyk’s Rosyred’ has similar flowers but of a lighter red colour.

‘Panda’ has white flowers and is very hardy. ‘John Cairns’ is a dark orange-red colour.

‘Kirin’ is a beautiful deep rose-pink in colour with a silvery touch and hose-in-hose flowers. ‘Hinomayo’ has pink flowers, and is very free-flowering and reliable.

‘Hinored’ is similar but with red flowers instead. ‘Addy Wery’ has rich orange-red flowers, a well known variety.

‘Rosebud’ is late-flowering with hose-in-hose flowers in a pretty shade of rosy pink. ‘Mother’s Day is an outstanding variety, hardy with very large bright red flowers, quite early to flower.

‘Beethoven’ has large pale purple flowers. ‘Orange Beauty’ has orange-red flowers on a loose bush. ‘Palestrina’ is white with a distinct greenish tinge, a lovely cooling colour for the flaming tones of other varieties.

Small plants

Because they are relatively small plants and will not ever grow very big, they suit small gardens nicely.

In a large garden, azaleas should be placed in a position close to paths or driveways where they will be seen to best advantage.

But they will be in flower for only a few weeks and will then revert to their more ordinary green existence.

While they remain as handsome, well-shaped plants when out of flower, they should not be in a position where their summer plainness is too obvious.

Weeds should be controlled for the first few years to allow good establishment. After that, these azaleas are quite good at shutting out the light to weeds beneath and are generally able to cope with a light weed cover at their base.

The best way to grow them is to mulch every couple of years with rotted leaves — this feeds the azaleas, helps to change the soil to acidic, retains vital moisture, and keeps weeds down. These azaleas are widely available in garden centres now in their flowering season.

If there is an annoying side to having a garden pond or other water feature, it is the growth of green algae in summer.

There are two main kinds: blanket weed and single cell algae. Both kinds bloom during the early to mid-summer, the blanket weed floating and the single-cell type turning the water green.

After mid-summer the water often gets too warm and the algae dies. The reason the algae bloom in the first place is that the nutritional status of the water increases, due to fish droppings and wind-blown leaves breaking down.

An old trick is to put a bale of straw, ideally barley straw, into a pond, the amount reduced for smaller ponds, as barley straw releases dark substances that inhibit the growth of algae.

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