Azaleas are hardy and half-hardy deciduous and evergreen shrubs.

Azaleas are most conveniently divided into three groups from the gardener's standpoint.

One of these comprises Azalea indica and its many varieties, all best treated as greenhouse pot shrubs, though they may be grown outside in very warm and sheltered places.

These are all evergreen.

The second group consists of the vigorous deciduous azaleas of the Ghent, Mollis, and rustica flore pleno types, which are quite hardy and suitable for cultivation in shrubberies, shrub borders, and large beds.

The third section is made up of dwarf kinds, hardy and evergreen, which are admirable shrubs for the rock garden.

It should be understood that the distinction between azaleas and rhododendrons is purely a garden affair. Botanically they belong to the same genus. Azaleas require exactly the same type of soil as rhododendrons. They dislike lime and thrive in almost any soil that is free of it, but especially in one which contains an abundance of humus, preferably in the form of peat. Those who live in districts in which the soil is naturally impregnated with lime or chalk should not attempt to grow azaleas outdoors until special beds have been made up for the purpose. In this case it is wise to build up the soil above the surrounding ground level and not merely to excavate the existing soil and replace with fresh. Such built-up beds must be at least 2 ft. in depth and should be prepared with good turfy peat and lime-free loam in about equal parts. When constructing rock gardens it is not at all difficult to preserve one section entirely for azaleas and other lime-hating plants.

If the soil is not impregnated with chalk or lime, it is only necessary to dig it deeply. Should it be of a harsh or heavy nature, it will be improved by liberal dressings of horticultural peat and sharp sand. Nothing in the way of manure is either necessary or desirable.

All types of azaleas are grand town shrubs, for they are as resistant to the effects of soot and grime as most hardy rhododendrons, and do not in the least object to a certain amount of shade.

Planting of the deciduous species can be carried out at any time during the dormant season, that is, from leaf-fall, usually about the end of October, till the buds begin to burst in early spring. Preference should be given to periods when the weather is mild and moist. The evergreen Japanese and Kurume azaleas can usually be purchased in small pots, and in their case transplanting is best done earlier in the autumn or later in the spring. No pruning is necessary save for the removal of faded flower trusses.

The usual, and certainly the best method of obtaining a stock of Indian azaleas is to purchase strong plants during the autumn knocked out of pots. These are well set with flower buds. Pots should be selected for those which will just take the roots without having to cramp and crush them in. Peat and loam form the compost. Very firm potting is absolutely essential, and another important point which applies to all plants growing in peat is that ample room for water must be allowed on the surface of the soil.

The most favourable position during the following weeks will be in a greenhouse or a covered frame facing north. Heat will be quite unnecessary until the advent of frosty nights. The syringe must be used at frequent intervals, and abundance of air must be admitted night and day.

Azaleas in full flower should be housed in a cool structure, as this will prolong the life of the flowers. As the plants pass out of bloom the decayed blossoms must be carefully removed, and they may then be staged in a heated house. The great point about successful azalea culture is the building up of the ensuing season's flower buds, and to this end warm conditions immediately after the flowering period will prove most valuable. The house must be kept moist and the plants syringed frequently and regularly. When the plants are well set with bud, judicious feeding with weak liquid manure will be most advantageous. Towards the end of July the plants may be placed in the open air, choosing a position with a northern aspect, away from trees, but sheltered from rough winds.

Although azaleas do not require annual repotting, the plants should be inspected every year after flowering, and for those that are not potted a surface dressing of sandy peat will be helpful.

Azaleas are not easy plants for the amateur to increase. The most satisfactory method is to strike short cuttings of half - ripened young growth in very sandy peat or even in pure silver sand in a frame with gentle bottom heat. Seed is very small and should only be covered with the finest scattering of silver sand. It can be germinated during March in a cool greenhouse.