Plant of the Week 5/9/2009: Indica Azaleas

(Ericaceae) Botanical name: Rhododendron x indica.

Culture: Azalea x indica are excellent performers in Sydney. Originating from Southern China, India and the highlands of Thailand; Southern Indica Azaleas grow into a 1.5 to 2 metre ball they are frost hardy but drought tender. Sydney's climate is well suited to Azalea growth as they prefer wet Summers and dry Winters. (zones 7 - 9)

Position: Southern Indica Azaleas are fairly robust but the full force of our Sydney sun in Summer can burn the leaves on those really hot days. Ideally Southern Indica Azaleas should be planted so they receive dappled light to light shade in Summer, and full sun to dappled light in Winter.

My late grandmother had a novel sense of fun because she mass-planted Indica Azaleas under each bedroom window of her home: If ever anyone tried to sneak up to peer through her bedroom windows, they would have become liberally covered with hundreds of the very sticky, bud-caps that transfer onto anyone who attempted to brush past these spectacular blooms.

Flowers: Azalea indica flower in August through to October. Colours range from red, reddish-crimson, crimson, clear pink, soft baby pink, salmon and white depending on the variety. A. x indica 'Alba Magna' (aka Alba Magnifica) is white, 'Alphonse Anderson' is a soft pink with a crimson centre, 'Magnifica' is a bright lolly-pink with a crimson centre, 'Schryderii' is white with a mauve centre, and 'Splendens' is a soft salmon-pink.

Care: Indica Azaleas like moist, but very free-draining acidic soils enriched with plenty of organic matter. Sensible Azalea horticultural practice is a far better alternative than spraying chemicals into your environment; and from my observations leaf miner outbreaks only seem to occur when they receive too much water in Winter. Furthermore, petal blight can largely be mitigated by watering Azaleas around the root-zone instead of watering from overhead.

Propagation: Half-hardened cuttings or layers provide the best material for propagation. Interestingly, some Indica Azaleas "sport", whereby one might end up with a shrub that shows half 'Alphonse Anderson' blooms and half 'Magnifica'.