Azaleas

Azaleas are part of the rhododendron group. Although there are deciduous azaleas that are popular in cold climate gardens, the azaleas seen in temperate and subtropical gardens are evergreen shrubs grown for their beautiful flowers, which are pink, red, purple, white, apricot or bicolour and may be single, ruffled or double. Azaleas flower in late winter to early spring and may spot flower in autumn and early winter.

Azaleas are grown as a flowering shrub for their massed displays of early spring flowers. They can also be grown as an evergreen hedge, potted plant, or as topiary specimens.

Large evergreen azaleas are often referred to as indica hybrids. There are also small-flowered kurume hybrids that are good garden or potted azaleas.

Growing conditions

Aspect Azaleas need a lightly shaded to sunny location. Ideally, they prefer morning sun with afternoon shade, especially in hot climates and will grow under the dappled shade of trees.

Soil Azaleas grow best in a slightly acid soil pH (around 5.5-6) that is ideally deep and moisture retentive.  To improve the soil before planting add home-made compost and organic matter and/or Seasol Super Compost. In areas with alkaline soil, grow azaleas in large containers with a premium potting such as Seasol Advanced Potting Mix.

Climate Although most evergreen azaleas are temperate plants, they grow in all climates. In cold areas, they need protection from cold winds, frosts and snow and are best in full sun. Frosts can damage flowers.

General care

Watering Adequate and regular water during bud formation and flowering is important as water stress at these times can lead to loss of flowers however, established azaleas are drought tolerant. Water regularly if plants are in hot, dry or exposed conditions or if they are growing in containers.

Feeding and mulching Feed throughout the seasons using a complete fertiliser for flowering plants such as Seasol plus Nutrients Roses & Flowers. Supplement feeding with a liquid fertiliser such as PowerFeed PRO SERIES for Roses & Flowers  every 2 to 4 weeks. Plants in containers can be liquid fed every 2 to 4 weeks while they are growing and flowering. Apply PowerFeed PRO SERIES Roses & Flowers or PowerFeed All Purpose including Natives. Regular applications of Seasol also assist drought hardiness and disease resistance.

Mulch all azaleas well with organic mulch such as lucerne, sugar cane or straw. Also add well-rotted manure and leaf mulch, which helps keep the root area cool.

Pruning Azaleas need little pruning unless they are being grown as hedges or trained as topiaries. Prune after flowering in spring to avoid reducing flower production. Old or unshapely plants can be cut back hard if they need to be rejuvenated however, avoid heavy pruning in summer as the exposed branches can be sunburnt. Ideally cut old plants back in stages allowing pruned areas to recover and grow before pruning the rest of the plant.

Watch for Azaleas do have some pest and disease problems. Azalea lace bug can attack the underside of the foliage in spring causing the leaves to develop a bronzed appearance on their upper surface. Prune off badly affected branches. Plants in semi-shade may not be as badly affected as those in full sun. Spray under the leaves with a natural insecticide such as EarthCare Enviro Pest Oil insect spray.

A fungus called petal blight causes the petals to appear wilted. As the disease progresses flowers become brown and papery in appearance and may be held on the plant. To prevent or delay this disease, apply a registered fungicide as the buds begin to colour and repeat applications during flowering as directed on the container. Lightly prune after flowering to remove affected flowers.