Gardening: Going troppo

Rhododendron 'Jaffa' are just the flowers to spruce up a garden in the summer time. Photo / Supplied

Guest garden writer Simon Farrell sings the praises of tropical blooms.

With a summer insisting on following the Dave Dobbyn lyric "There's a cloud the full length of these isles just playing chase with the sun" it's time to forget the heavens and focus on the earth.

Flowers still hold sway in cheering up the garden and, at this time of year, you can indulge in blooms that remind you of the tropics.

Three species that always deliver on cue are tropical rhododendrons, hibiscus and the irrepressible canna lilies.

Tropical rhododendrons, vireya, are some of the most attractive woody shrubs on the planet.

If roses are the queen of flowers then vireyas are the princesses-in-waiting - elegant, vibrant and not a thorn in sight.

They flower whenever they like, up to four times a year, come in many colours, and some are gorgeously fragrant.

A lot of work has been done in selecting varieties with trusses of large flowers, large leaves and compact growth.

Keep an eye out for 'Double Happy', 'Captain Scarlet', 'Lolita' and 'Jaffa'. These are seriously good varieties for underplanting palms because the dappled light is perfect for the health of the plant.

Get the planting right on day one and these dazzling shrubs will have you wondering how life was without them.

Hawaiian hibiscus are atypical of many flowering woody shrubs as they celebrate spring by slipping into dormancy.

They often fool the uninitiated into believing that the yellowing, black spotted, falling leaves and lacklustre appearance indicate sinister ailments.

Not so. By late November they wake up, shout "Aloha", then brazenly flower continuously for five or six months.

Hibiscus have a substantial appetite for plant food and love a mix of direct sun and shade, all the while blooming their hearts out.

What I loosely term a super perennial, the canna lily has an indestructible charm. Whether your colour preference is red, yellow, orange or pink, there is a canna for your garden.

Their cane-like stems and bold foliage add a lush tropical feel to a garden. They're a clumping plant so, over several years, become a major source of flowers and their blooms have a reasonable vase life.

Being perennials, the annual chop-back of all these plants is best done when you're in need of a workout. I find swinging a machete into the base of Cannas a great stress reliever and it results in a pile of green waste for the compost heap.

Unlike hibiscus and vireya, cannas can cope with all sorts of soils. Indeed, they grow remarkably well in bog gardens, and make a real spectacle next to ponds where their roots can slurp away all summer long.

Tropical tips:

Vireya rhododendrons

* They fare better with the top of the root system just above the ground level.

* They hate wet feet and won't grow in a clay sump. Mix compost, topsoil and fine pumice or drainage metal to make a planting mix.

If you have clay soil, grow your vireyas in pots.

* They dislike heavy shade, preferring morning sun and afternoon shade.

* Protect against frost.

* Slow-release fertiliser is beneficial in the early years.

* Vireyas have a fine, fibrous, shallow root system that gets baked in summer. Avoid this with a 5cm to 10cm mulch.

Hibiscus

* They respond well to a mix of composted organic material and slow-release fertiliser.

* Feed them at Labour weekend as they break their dormancy.

* Protect them from frost and mulch well.

Canna lily

* In terms of ground preparation they are far less fussy than vireyas and hibiscus.

* Like all plants they respond well to feeding - sheep pellets are a good start.

* Water in the dry months and surround with plenty of mulch to get fast, tall, lush growth.