Subtropical plants are grown predominantly for their striking foliage and flowers. As an additional benefit many also have bright flowers (in particular gingers and cannas) and heady fragrance (gingers). While some of these plants require mild, nearly frost-free conditions others will tolerate extreme cold.
One cannot discuss subtropical plants without reference to bananas. From the common fruiting banana to red and pink fruited species, variegated leafed, giants to miniatures, hardy to tropical there’s a banana plant for any garden. Favourites of ours include the giant Ensete ventricosum and its red cousins Ensete ventricosum ‘Maurelii’ and Ensete ventricosum ‘Montbeliardii’ as well as the tough pink fruited Musa velutina and the extra-hardy Musa basjoo. Given protection from the wind a clump of bananas will add a tropical feel to your garden.
We begin with the Bird of Paradise, a popular exotic plant in northern New Zealand. The two forms most frequently seen are the bright orange and blue flowered ‘common’ Bird of Paradise, Strelitzia reginae, and the giant white form, Strelitzia nicolai. The latter resembling nothing more than a very large banana tree growing to 6m or more. In addition, there are several other species and cultivars such as a rare yellow flowered plant and a reed-leafed species. Strelitzia are perfect for locations that experience no more than a light frost.
If you want beauty and a heady aroma on warm summer evening, then consider planting several species of ginger. Sadly, the entire ginger family has earned a poor reputation in New Zealand on account of just one species – Hedychium gardnerianum. Taking a sensible approach there are in fact over 1300 species of ginger, the vast majority of which pose no problem at all. Whilst some species of ginger are very tropical there are a number of species suitable for New Zealand including the Costus genus which includes plants that are hardy to -10°C. Favourites of ours include some of the non-invasive Hedychium species and hardier species of Alpinia.
Similar in size and appearance to the ginger is the Canna. Cannas have been used for years in New Zealand gardens and with a little effort, some particularly beautiful flowered cultivars may be found. Some species can grow over 3m tall and there’s even the Hardy Water Canna, Thalia dealbata.
Finally, in the ‘banana look-alikes’ there’s the gorgeous Heliconia family. Heliconias have the same banana-like leaves but flowers that put the Bird of Paradise to shame. Most Heliconias won’t grow in New Zealand but there are a handful of hardy species that’ll flower in a warm and sheltered northern garden.
A completely different collection of exotic plants with large leaves are the aroids. The aroid family includes such familiar plants as the Arum, Calla and Flamingo Lilies as well as the Taro. Like many of the plants we’ve described there are hardy and tropical examples. For northern New Zealand’s mild climate we particularly recommend the large Alocasias and Colocasias.
We’re all familiar with the native Cabbage Tree, Cordyline australis. What you may be less familiar with are the truly gorgeous cultivars of Cordyline fruticosa from Hawaii. These tender plants come in a range of colours – from pink to orange, black, green and yellow. They’ll need a frost-free spot in a coastal garden but if you’ve always thought Cordylines were boring, dull plants then think again.
In frost free locations in northern New Zealand you’ll find Clivias growing outdoors and blooming prolifically. With thick, strap-like leaves similar to the Agapanthus but masses of bright orange flowers the Clivia provides a splash of colour low down in the garden. New cultivars and species include red, yellow and cream flowered varieties.
Finally, there are the three hardy giants:
The Giant Rhubarb, Gunnera manicata, a hardy bog plant with monstrous leaves to 2.5m or more.
The Giant Butterbur, Petasites japonicus, another hardy bog plant, this one with leaves to a ‘mere’ 80cm.
The Rice Paper plant, Tetrapanax papyrifer 'Rex', which can grow to around 3-4m tall with leaves over 1m across.
See Garden Designs using Palms, Cycads and Subtropical Plants for more suggestions about combing palms with subtropical plants.