Azalea
Rhododendron spp. (azalea group)
Azaleas are flowering shrubs that smother themselves in blooms of pink, red, purple, white or orange in spring. Evergreen types suit pots and mild climates, while deciduous types are hardier. Like all rhododendrons, they need acidic soil.
Photo: albert kok · CC BY 3.0, via Wikimedia Commons
Essential Care Requirements
Light
Partial sun
Watering
Moderate
Keep the soil moist with rainwater; the shallow roots dry out quickly.
Soil
Acidic, humus-rich, well-drained soil; pH 4.5–6.0.
Temperature and humidity
-20–32 °C · Moderate humidity
Feeding
Feed after flowering with an ericaceous fertilizer.
Pruning and propagation
Propagate by stem cuttings, layering
Prune lightly right after flowering; later pruning removes next year's buds.
All parts are toxic to people and pets, and can cause serious heart and digestive problems. Honey from rhododendron nectar can also be toxic.
Top Cultivation Tips
Plant high, with the top of the root ball at soil level.
Mulch with pine bark.
Never let pot-grown plants dry out.
Indoor azaleas are usually given as gifts and need cool rooms.
Common problems
Iron chlorosis
Young leaves turn yellow while the veins stay green, usually because alkaline soil stops the plant taking up iron.
How to treat it →PestLace bugs
Small flat insects with lacy wings that feed under leaves, leaving the upper surface speckled pale and the underside spotted with black.
How to treat it →DiseaseRoot rot
Roots decay in waterlogged soil, so the plant wilts and yellows even though the soil is wet.
How to treat it →DiseaseSalt damage
Leaf burn and stunted growth caused by too much salt in the soil or water, from sea spray, road salt, hard water or heavy fertiliser use.
How to treat it →PestSpider mites
Tiny sap-sucking mites that thrive in hot, dry conditions, causing speckled, dull leaves and fine webbing.
How to treat it →PestVine weevil
Adult beetles notch leaf edges at night, while their soil-dwelling grubs eat roots, often killing container plants before you notice.
How to treat it →
