Please leave a comment , what grows where you are! People don't know, what they don't know!
Although this podcast covers specific information for New Zealand, the general information is useful anywhere thst growing tropicals is on the fringe of their niches.
Please send us questions, or comments, especially what you liked , so we can do more of what you want.
Great info can be found here . A really useful interactive map.
Fun fact of the day.
The highest temperature ever recorded in New Zealand was 42.4 °C (108.3 °F) on 7 February 1973 in Rangiora. The lowest temperature ever recorded in New Zealand was −25.6 °C (−14.1 °F) on 18 July 1903 in Ranfurly.
Bananas have been growing in Taranaki , successfully since 1890!
Some terms we will use.
Zones are based on the average lowest winter temperature, ranging from Zone 1 being the coldest to Zone 13 being the warmest.
Zone 1 is suitable for plants hardy down to around -50°C. Zone 12-13 are tropical zones that don't tolerate any frost or freezing, with average winter lows of 10°C or warmer.
Most tropical plants are well-suited for zones 10-13, which means they can handle average winter lows between 0-10°C. Some marginally hardy varieties may survive brief dips to around -5°C in Zone 9.
As always, microclimates vary, so a spot sheltered from wind and sunlight could increase your zone by one.
For example , your region may be a 8-9, but with a suitable microclimate , this becomes a 9-10 for your smaller area, allowing tropicals to do well.
A microclimate refers to a localized atmospheric environment that differs climatically from the surrounding area, due to certain geographic factors. Having an eye out for microclimates is important for expanding tropical planting zones down under.
Some signs of warmer microclimates to look out for include:
- Areas near large bodies of water like the coast which remain warmer than inland spots during colder weather. Our southern oceans provide significant temperature buffering.
- South and west-facing sheltered slopes maximize sun exposure in winter months compared to northeast aspects which are cooler and receive more rainfall.
- Pockets between structures like buildings, fences and dense vegetation that are sheltered from prevailing winds coming from the southeast in Australia or southwest in NZ.
- Low-lying damp areas where chilly air collects at ground level may be slightly warmer than high exposed ground.
- Urban areas tend to stay warmer than rural spots at night due to sun-soaked concrete radiating heat absorbed during the day.
- Evergreen windbreaks like tree ferns or bamboo groves hold warmth acquired through sunny days protecting tropical plants.
Being observant of such microclimate factors means tropical plant growers down under can push the limits of even zone 9 species in localized warmer microzones through our cooler seasons.
Here is an updated list including some additional Northland towns:
North Cape to Kaitaia -Zone 10/11/12a
Whangarei - Zone 10/11
Kerikeri - Zone 10/11
Auckland - Zone 10-11
Hamilton - Zone 8-9
Tauranga - Zone 9/10
Napier-Hastings - Zone 8/9
Palmerston North - Zone 7
Nelson - Zone 8-9
New Plymouth - Zone 8
Rotorua - Zone 8-9
Christchurch - Zone 8-9
Invercargill - Zone 7
Gisborne - Zone 8-9
Whanganui - Zone 7
Timaru - Zone 7
Taupo - Zone 7-8
Hastings - Zone 8
Wellington - Zone 9
Dunedin - Zone 7-8
Levin - Zone 6-7
Some changes to note - the very northern towns of Whangarei, Kaitaia and Kerikeri all provide excellent Zone 10 conditions for tropical plants. Wellington is warmer than first thought at Zone 9.
The Northland region starting from Whangarei all the way up , past Kaitaia to North cape has a truly tropical climate with minimal risk of frost. This area is paradise for growing heat-loving foliage. Further south the zones gradually decrease as you head toward the cooler climates near the bottom of the South Island.
Here are 10 of the warmest coastal areas around New Zealand for tropical plant growing, along with their estimated typical zones:
1. Northland - Zone 10
From Whangarei up to Mangonui, and North cape, the entire coast provides a true tropical environment unmatched elsewhere in NZ. Ideal for zone 10-11 species.
2. Northeast Auckland - Zone 10-11
Areas like Mangawhai, Bucklands Beach and Northern Wairoa are about as warm as it gets, allowing even frost-tender exotics to survive winters.
3. Coromandel Peninsula - Zone 9-10
The eastern waters keep spots like Whitianga and Whangamata on the warmer side of the range ideal for zone 9 plants.
4. Bay of Plenty - Zone 9-10
Welcome Bay down through Mt Maunganui exploits the sea temperatures, pushing the boundary for bananas and citrusbto grow well.
5. Gisborne - Zone 8-9
Coastal suburbs take advantage of the warming marine influence, being a reliable habitat for zones 8-9 species. Some fantastic bananas are coming out of Gisbourne now
6. Marlborough Sounds - Zone 8-9
Despite southerly latitude, the protected waters allow Lizard Point and Havelock to grow tropical foliage at limits.
7. Nelson - Zone 8-9
With sea on three sides, towns like Mapua enable fringe hardy palms and bananas, red pineapples with TLC through occasional frosts.
8. Banks Peninsula - Zone 8
Bays like Lyttelton provide enough maritime buffer against Canterbury cold spells for ginger lilies and screw pines.
9. Dunedin - Zone 7-8
Despite a southern location, St Kilda allows citrus tree survival through mild winters by the ocean.
10. Southland - Zone 7-8
Riverton's proximity to Foveaux Strait creates a minor warming, welcoming tropical edging plants.
Tips for improving the microclimate , so everything grows better.
Having a shelter belt , taller trees, mounded mulch, black weed matting all provide site modifying factors.
If you have a blank canvas in a marginal Zone, there are several things you can do to create your tropical paradise .
Firstly is to create a windbreak.
Six ft high fences don't provide good windbreaks, the wind flows over the fence and then has higher wind speed that causes swirling winds that damage plants .
A soft windbreak, such as 15%-30% windbreak causes wind to slow as it passes through causing a lot less damage and allowing light through also, a bonus! These are used in avocado orchards , because it works!
Using thermal banks is another way to create extended warmth. Brick walls have been used for hundreds of years. For example England in the 1800s , oranges and mandarins were only grown in other places such as Spain. But by using brick walls that absorb sunlight, and then radiate heat during the night, ensuring a higher overall temp.
Water tanks also do similar.
House walls can also reflect light and heat increasing a local temperature.
It's also best to start with more hardy tropicals, such as Red pineapples, misi luki bananas , or tropical guavas.
Spanish greenhouses refer to the unique-style greenhouses used by farmers in Southern Spain for growing tropical plants like tomatoes, peppers and cucumbers, also useful for papaya, and mangos. They have some defining features:
- Solar heating - The greenhouses are oriented with their long side facing NE or NW, so they can take full advantage of solar heating during the day. Tall arched roofs further maximize sunlight entry.
- Thermal mass - The walls and floors are made with dense materials like brick, concrete or stone that absorb heat during the day and release it slowly at night. This maintains warmer overnight temps inside.
- Ventilation , Vents at each end of a greenhouse allow air flow. Automatic window openers are really useful, which use pneumatic openers and don't need electricity. Manual windows are a recipe for killing everything. The day you are out, and forget to open the windows will lead to temps of over 40 degrees that will cook your plants causing heartache and tears.
- Irrigation - Drip, sprinkler or mister systems keep plants hydrated without wetting foliage which could promote disease. Subsurface drip is also popular.
- Crop choice - Heat-loving vegetables are ideal since they thrive in the warm, humid conditions maintained all year. Tomatoes, cucumbers, peppers, papaya, pineapples and melons do especially well.
Here are the top 10 warmest Auckland suburbs for tropical plant growing, along with their estimated zones:
1. Howick - Zone 10-11
Situated on the east coast near the Firth of Thames, coastal breezes help moderate temperatures making it one of the warmest parts of Auckland. Excellent for bananas, jackfruit, and other frost-sensitive tropicals.
2. Pakuranga - Zone 10-11
Enjoys a sub-tropical climate along with Howick. Protected valley location is ideal for zones 10-11 plants like philodendrons, bird of paradise, canna lilies and most Tropicals.
3. Mellons Bay - Zone 10
On the North Shore coast near Devonport, with ocean influencing warmer microclimate. Spanish greenhouses thrive here all year around. Also sensitive bananas, and mangoes
4. Bucklands Beach - Zone 10
Coastal village also benefits from sea temperatures, permitting tropical palms sensitive bananas and agaves to survive winters outdoors.
5. Pinehill - Zone 10
Sheltered hill suburb perfect for tropical fruiting trees like mango, carambola and loquats.
6. Botany - Zone 10-11
Coastal flats keep temperatures up, growing bananas, guavas and passionfruit without protection.
7. Stanmore Bay - Zone 10
On Whangaparaoa Peninsula with water maintaining climactic buffer from frost. Orchids, hibiscus happily prosper, along with most Tropicals.
8. Mission Bay - Zone 10
Top rated beachside neighbourhood lets tropical exotics like gingers, heliconias stay outside year-round.
9. Glendowie - Zone 10
Northeast valley provides frost shelter allowing tropical plants to stretch their limits here.
10. Kohimarama - Zone 10
Affords coastal microclimate advantages for palms, cordylines along with its beaches!
And finally , if after all that info , you would rather talk about your garden, orchard or farm with us, we do this too. We offer Skype online bookings around the country, or locally , in person evaluations and potential reports .
Have a great day.
I only wish I'd planted more plants two years ago...
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