Marilyn Wightman highlights some tropical additions that grow well in New Zealand soil.
Herb plants native to tropical climates usually experience a season of high humidity and rainfall (summer), followed by a season of cooler temperatures and dry conditions (winter). We are an island nation surrounded by sea and, being too far south of the equator, our climate just does not suit many tropical herbs.
At a herb conference in North Queensland, I had a fascinating glimpse into a different flora set – frangipani, jojoba, patchouli, vanilla vines – all growing luxuriously in their July winter climate, averaging 25˚C temperature. Perhaps this gives an understanding of why it is impossible to find some tropical herbs in New Zealand.
We often utilise dried and imported products to enjoy the flavours of such herbs, however, there are still a select few that will grow happily at your house. As well as basil, rice paddy herb, coriander and lemon grass – all of which we have highlighted in past issues – here are some exotic herbs that don’t mind the Kiwi climate.
Ginger (Zingiber sp.)
Available in many forms for our gardens. One is the frost-hardy myoga ginger (Zingiber mioga), a Japanese variety that traditionally has its flowers stuffed and eaten as a delicacy. Consult your local garden centre about the type that grows best in your area.
Mexican mint (Plectranthus amboinicus)
A succulent with fleshy leaves. Only a small piece – the size of a 50c piece – is broken off to use in stir-fry dishes and casseroles. Its flavour is similar to the packaged dried herbs we use for seasoning roasts and slow-cooked meals. Grow it as a house plant and put outside for the summer months.
Aloe vera (Aloe vera)
Exhibits yellow flower spikes in October and November. Many varieties are wrongly called Aloe vera, but the yellow flower distinguishes the medicinal kind. Grow it in tubs and place outside for summer sun, but bring back indoors over winter for frost protection and warmth.
Sugar cane (Saccharum officinarum)
Grows over 2m tall. It grows like bamboo, sending shoots upwards, and will survive outside under the shelter of trees or in a frost-free garden. The cane is cut and pulverised to release the juice. In this form, with no cooking or refining, its enzymes provide healthy nutrients. For full growing details, check out the article in the Planting Guide.
Gotu kola (Centella asiatica)
A low ground cover, with new shoots that creep along the ground. It cannot survive outside well and is best grown as a hanging indoor plant. The new shoots will dangle down the sides to make
an attractive feature. It needs high humidity to succeed well. Provide this by standing the container in a saucer that gets topped up regularly with water.
Tropical herbs you will have trouble growing:
Allspice, carob, cinnamon, clove, cocoa, coffee, frankincense, murraya, myrrh, nutmeg, pepper, sandalwood, true cardamom, turmeric, vanilla.