Rhododendron season


Want an aristocrat in your garden? Well, grow a rhododendron – it will add a touch of class to any home landscape.

Rhododendrons and azaleas are botanically very closely related. In fact they’re part of the same plant family. But rhododendrons have a long-established reputation for only growing happily in cold mountain gardens with deep soil and high rainfall.

That’s no longer true. In recent years we’ve seen an influx of what are termed ‘tropical’ or vireya rhododendrons. Unlike the Himalayan varieties – that were taken to Europe and then subsequently made their way to the southern hemisphere – vireya rhododendrons come from places like Indonesia, Malaysia and New Guinea. There is also an Australian native species, the red-flowered Rhododendron lochiae. Vireyas’ warm climate origins mean that they can be grown in many parts of New Zealand. Some originate in highland areas, so they’re reasonably cold tolerant, but almost all dislike frost.

Vireya rhododendrons are differentiated from the Himalayan varieties by their glossy leaves, long flowering period and unusual colours. Many of the vireya flowers come in shades of orange and salmon as well as the more traditional rhododendron pink and white.

Vireyas don’t produce the massed show that’s so typical of the cold climate rhodos but, unlike their spring-blooming cousins, they continue flowering over many months.

Grow vireyas in a spot with extra good drainage. Some are tree dwellers in their native habitat so they’ve evolved to survive on the moisture that collects in leaf litter around their roots. They appreciate dappled shade and will grow happily with a few hours of morning sun. Keep a layer of light mulch over the roots and feed in spring after the first flush of flowers. Use Yates Thrive Azalea, Camellia & Rhododendron Food, but make sure it’s watered in immediately after application.

Cold climate rhododendrons are, understandably, happier in cooler areas. In fact, Rhododendron ponticum has done so well in the UK that many people think it’s a native. Cold climate rhododendrons, with their leathery leaves and massed flower display in spring, have become the backbone of many New Zealand gardens, too. Plants produce a spectacular spring show, with the flower trusses almost covering the evergreen leaves.

All rhododendrons appreciate acidic, humus-rich soil. Dig plenty of old cow manure, pre-moistened Hauraki Peat and half-rotted leaf litter into the bed before planting. Smaller varieties grow happily in pots. Use a good quality potting mix (Yates Premium) and a good-sized pot.

Pest problems are few, but leaves are often attacked by sap sucking insects. Start spraying with Rose Gun in the early spring to protect the new growth throughout the season. A once-a-month spray may be all that’s required. Feed and do any required pruning – pruning may not be necessary – immediately after the flowering period.


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