Keeping Azaleas Indoors
One of the most colourful and prolifically flowering houseplants, indoor azaleas' vivid pink, white and red blooms are an absolute delight that lift the mood during the winter months. The indoor variety (also known as greenhouse azaleas) are close relations to the hardy outdoor azalea – both are from the rhododendron family – but hardy azaleas won't be happy indoors, while indoor azaleas won't survive freezing winter temperatures outdoors, so it's important that you distinguish between the two when buying a plant to bring home.
When selecting an indoor azalea, look for a plant with dark green, compact foliage, plenty of buds that are just colouring and a sprinkling of open blooms. Avoid plants with yellowing leaves or dry soil, and check beneath the leaves for signs of whiteflies or other pests.
Caring for your azalea
It's important that your azalea receives plenty of light, but avoid placing it in direct sunlight. Keep it away from direct heat sources too, such as radiators. Indoor azaleas do best at temperatures between 16°C and 18°C.
Moisture is vital for the health of azaleas, so it's important that they are not allowed to dry out completely. Water regularly and on occasion submerge the whole pot completely in a sink or bucket of water until bubbles have stopped rising from the soil, then allow the excess water to drain away. While the plants thrive on moisture, don't leave them in standing water as this is likely to lead to root rot.
Azaleas do best in acidic soil. In alkaline soils, they can't absorb enough iron, and the result is chlorosis – leaves turning yellow or white between the veins. This is often a problem in hard water areas, as the tap water is slightly alkaline. If you are in a hard water area, water your azaleas with collected rainwater or distilled water, not tap water.
While the plant is flowering, feed monthly with a liquid houseplant fertilizer suitable for plants that prefer acidic soil – a PH in the range of 5.0 to 5.5 is best.
Pruning your azalea
To keep your azalea's shape and encourage new growth, prune it after flowering, using secateurs to cut the stems at an angle just above the leaf nodes. Ensure the secateurs are sharp to avoid tearing and crushing of stems, and sterilise the blades using boiling water to minimise the risk of spreading infection between plants.
Trim any brown leaves and petals and ensure you remove any plant material that lies on the soil. If left, dead leaves and petals can rot and cause disease.
Azaleas are often given as gifts and discarded after one winter, but with the right care it is possible to see them flower year after year.
In order to get your azalea to bloom again it needs to lie dormant for several months. Leave it outdoors in a shaded place during the summer, water sparingly and don't feed. In autumn, before the first frosts, bring it back indoors and keep it in a chilled, sunny location, with temperatures between 4-10°C. This will promote the development of flowerbuds. In late winter, move the plant to a slightly warmer location (around 16°C). Flowers should start to open within a couple of weeks.
Repot your azalea every two or three years, ideally in the late summer or early autumn.
Important note: Azalea plants are poisonous if consumed. Keep them away from children and pets.