Sandra SimpsonA tropical garden in the subtropics

We all want to create our little corner of paradise in our gardens and it’s fair enough that Kiwis look to the tropics for inspiration, after all, most of us have had a memorable South Pacific or north Queensland holiday.

Vireya 'Tropic Glow'

Vireya ‘Tropic Glow’

The bad news is that we live in the sub-tropics which means we can’t have a true “tropical” garden as it’s not only about temperatures and rainfall but the almost unvarying levels of daylight through the year.

The good news is we can achieve “tropical-look” plantings if we do our homework and are clever about plant choice.

Palms are the backbone of any tropical garden and while we can’t grow the coconut palms so typical of an island paradise, we do have access to a range of trees to suit our climate.

Creating layers of planting – canopy, sub-canopy, under-storey and groundcover – creates depth and gives the impression a garden is bigger than it actually is.

Bendy bangalow palms in the Palmco garden, Kerikeri

Bendy bangalow palms in the Palmco garden, Kerikeri

Large trees and plants include Parajubaea cocoides (Quito mountain coconut palm) that can handle strong winds and hard frosts; Chatham Islands nikau (Rhopalostylis sapida); Atherton palm (Laccospadix australasica) from Lord Howe Island (not below minus 2 degrees C); the fish-tail palms Caryota ochlandra and Caryota obtusa; the smaller Dipsis boroni (hardy sugar cane palm); Strelitzia nicolai (giant bird of paradise, looks like a banana palm); banana palms; and Meryta sinclairii (puka) which although frost tender, can be grown in shade.

In the display garden at Palmco in Kerikeri they have created a coconut palm effect by planting bangalow palms on an angle – as the trees straighten up and grow towards the light, a bend develops in the trunk.

The white-flowered variety of Justicia carnea, the Brazilian plume flower

The white-flowered variety of Justicia carnea, the Brazilian plume flower

Other plants to help the island paradise feel include hibiscus, bromeliads, taro, gardenias, hostas, pineapple lilies (eucomis), canna lilies, vireya rhododendrons, ligularias, star jasmine, orange jessamine (Murraya paniculata), cymbidium orchids, hoya and clivia. Smaller hardy orchids, such as Australian Dendrobiums or Zygopetalums, can be grown on trees or in ponga posts.

Native plants that add a touch of the tropics include rengarenga lilies (Arthropoduim cirratum), Chatham Island forget-me-nots (Myosotidium hortensia), ferns and tree ferns.

If you don’t have room for a pond, water lilies can be grown in a half-barrel or a large, glazed pot.

And don’t omit bamboo from your line-up just because of its weedy reputation. Choose carefully and it will add a grace to your garden that few other plants can achieve.

Cordyline fruticosa 'Fiji' in Wharepuke garden

Cordyline fruticosa ‘Fiji’ in Wharepuke garden

Robin Booth of Wharepuke garden in Kerikeri finds that once an area is planted, plants create their own micro-climate and “support one another”.

He imported Cordyline fruticosa ‘Fiji’ in to New Zealand “many years ago” and says the small tree with its brightly coloured leaves will do well in a cooler climate. New Zealand grass trees (Dracophyllum) are another shrub-size alternative.

For more information and to buy plants, try these specialist New Zealand websites:

Bamboo (see also Landsendt)

Bromeliads

Cycads

 

Ferns: Millhenge Ferns at Oropi specialises in native ferns, including tree ferns (Cyathea and Dicksonia). Phone 07 543 2149, or email.

Landsendt (Auckland) is a highly regarded and well-established tropical-look garden that has a nursery

Palms – Coast Palms and Cycads or Palmco

Russell Fransham (Northland) specialises in subtropical plants

Sub-tropical cordylines (article)

Vireya rhododendrons

Water lilies.

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Sandra Simpson

About Sandra Simpson

Sandra Simpson is a long-time journalist who in 2008 was asked to write a weekly garden feature for her local daily newspaper in Tauranga, New Zealand. Since then she’s visited beautiful gardens, met great people and attended several shows. In 2012 she started her own blog, Sandra’s Garden to share more of the people, places and events that make her corner of the world so bountiful.

4 thoughts on “A tropical garden in the subtropics

  1. That’s a really clever idea about planting bangalow palms on an angle to get that coconut palm look. I’ve seen them copse-planted to great effect but not on an angle. Sydney landscape architect Bruce Mackenzie often planted small eucalypts like scribbly gum on an angle to get a much more natural silhouette.
    And that photo of the vireya! No wonder it’s called ‘Tropic Glow’!

    • Sandra on said:

      Hi Catherine,

      Yes, the people at Palmco do a bit of thinking “outside the box” and their show garden in Kerikeri (Bay of Islands, the north of the North Island) is well worth a visit.

      And thanks for the photo compliment, much appreciated.

  2. I’m fascinated, Sandra, by the comment about unvarying daylength. Is the idea that truly tropical plants don’t cope with the variation in daylength that occurs further from the equator? How does it effect them? I had always just assumed that minimum temps were the only problem..

    • Sandra on said:

      Hello Michael,

      I’m glad you found the article interesting. I confess that the idea about the unvarying day lengths was intuitive – I know that some plants need a change in day length to flower but in researching this answer found that it’s actually the change in night length that’s important (scientists confusingly still refer to it as “short-day”, “long-day”, while all knowing that the first theory was in error!).

      This comes from “The Causes of Flowering”, a paper published in 1956 by I M Sussex at Victoria University (Wellington, NZ) and which is available online:

      “In their native habitats plants seem to have adapted their flowering response to the day-lengths which they normally encounter. Thus species which are native to the tropics, where day-lengths tend to be constant at about 12 hours throughout the year, are generally short-day plants, those from more temperate regions, which have longer summer days, are often long-day plants. This explains the frequent failure of plants moved to new geographical regions to flower despite the favourable temperatures in which they are grown.”

      There are also day-neutral plants in temperate regions (such as tomatoes which don’t need a light/dark trigger for flowering) while I’ve read that “spinach … cannot flower in the tropics because the days never get long enough (14 hours)”.

      So getting tropical plants to flower as well outside the tropics is probably a combination of day length, temperature and wet/dry – and speaking as someone who is still getting to grips with cool-growing orchids from tropical regions, aaargh!

      Hope that some of this rather long answer is helpful …

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