Indoor Azalea – Rhododendron simsii

In its natural habitat in southern China, the Indoor Azalea lives in cool, very moist and very humid conditions. It normally blooms in the spring, but in Britain it is usually available as a forced plant that is grown to produce flowers from the autumn until the spring. When your plant is in bloom, water it regularly with a weak feed in soft water. Make certain it never dries out, and it will flower for up to a month. Plants that are being brought into flower for the second year should be misted daily in late summer and autumn to encourage buds to form.

Azaleas are constantly being improved and refined and there are therefore many strains to choose from. Most people buy according to the colour of the flowers. These plants come in many shades and hues of white, pink and red; there are plants with crimson, magenta, orange and salmon flowers, and single or double blooms.

Size and growthIndoor Azalea - Rhododendron simsii

Plants are usually 13– 30cm (5-12in) tall when they are sold, and resemble small bushy trees. Very occasionally they are available as standard-trained ‘trees’ — but these are expensive.

Display ideas

Like most flowering plants, Azaleas are best grown as specimen plants or with a group of foliage plants, so that the beauty of their flowers can be seen to the best advantage. Give them fairly cool conditions to prolong flowering.

A year with your plant


Autumn to spring is the time to buy plants. If you plan to keep your Azalea until it flowers a second time, reduce the amount of water you give it after it has finished flowering, but never let it dry out completely. Put it in a light but cool position; 4°C (40°F) is ideal.


In summer, your plant will benefit from a period outdoors in a warm, shady spot. Choose a position where it will not be forgotten, as regular watering and feeding are essential. Before putting it outdoors, transplant it into a pot one size larger.

September–October Bring the plant inside before the first night frosts and keep it cool. Do not allow it to dry out; if it does, put the whole pot in soft water at room temperature for 15 minutes. Allow surplus water to drain away.

You can also do this once a week throughout the flowering period, and mist spray the plant daily.

Plant Problems

  • The plant will lose its leaves if it has dried out or been exposed to a draught.
  • Prevention: Always keep the compost moist and stand the plant in a sheltered position.
  • Aphids may appear on flowers buds and on young leaves.
  • Treatment: Spray with an insecticide, and repeat treatment if necessary.
  • Yellow leaves and growing tips occur if there is too much lime in the potting compost. Prevention: Always use soft water and an ericaceous potting compost. Ericaceous compost is a peat-based compost generally available from garden centres and nurseries.


This is a demanding plant that must have lime-free water and humid conditions as well as a fairly cool position. It may be necessary to pinch out overly strong shoots if the plant is to be kept for a second year.

Potting: Pot on in summer using an ericaceous (all-peat) potting compost.


Water your plant generously in the summer and moderately in winter. It is important that the roots are never allowed to dry out. Use lime-free soft water, such as clean rainwater.

Feeding: Feed from March to August with a standard liquid fertilizer. Dilute the feed to half its normal strength when the plant is in bloom.


Light: Keep your plant in bright light but away from direct sunlight.

Temperature: Maintain the temperature at 10— 15°C (50-60°F). Your Indoor Azalea will tolerate normal summer temperatures if kept outdoors in summer in a sheltered position.

When to buy

Indoor Azaleas are widely available when in flower, from November onwards, from florists, supermarkets and nurseries.

What to look for

Choose a plant with good, bushy growth and lots of plump green flower buds, some of which show signs of colour.


Although it is mainly treated as a short-lived gift plant, the Indoor Azalea (given proper care) can be kept to flower a second year.

From a botanical standpoint all azaleas are rhododendrons, but in nursery catalogues they are usually listed separately. Some varieties are evergreen and some are deciduous, and these differ greatly in appearance. The evergreens mostly have small leaves and a rather twiggy, densely branched habit and small to medium-sized flowers in shades of pink and lavender to scarlet and crimson, plus white, whereas the deciduous azaleas have larger leaves, often turning crimson in autumn, a more open habit and larger flowers in shades of yellow, orange, coppery red, crimson and white. The flowers of some deciduous kinds, particularly the common yellow, are spicily scented.

All flower in spring or early summer and grow best in lime-free, moderately acid soils and half-shaded places, but the deciduous varieties will also grow well in full sun provided that the soil is not dry. It pays to work in plenty of peat or leaf-mould before planting and to topdress with either or both each spring. Pruning is usually undesirable, but badly placed branches can be cut out in spring, immediately after flowering.


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