Ground contact, exposure and budget narrow the field before appearance does.
Timber choice for landscaping is often driven by how it looks in a photo, but the more useful starting question is what the timber actually has to withstand: is it in ground contact (a post, a raised bed wall) or above ground (decking, screening)? Is it exposed to weather and possibly salt, or relatively sheltered? Treated pine, macrocarpa, hardwood species and thermally modified timber all perform differently against those two questions, and the right one for a fence post is not necessarily the right one for a deck board.
This guide compares the main options New Zealand landscaping projects typically choose between, organised around durability and appropriate use rather than appearance alone.
01 · Compare the main options
Four timber options, compared for landscaping use.
Treated pine (H3/H4/H5)
Best useWidely used across fencing, decking and retaining depending on treatment grade
DurabilityTreatment class (H3 above ground, H4/H5 ground contact) needs to match the actual application
CostGenerally the most budget-accessible option
Macrocarpa
Best usePopular for its natural durability and warmer appearance in exposed applications
DurabilityNaturally more durable than untreated pine, though still benefits from correct detailing in ground contact
CostMid-range, and supply can vary regionally
Hardwood (e.g. vitex, kwila-type species)
Best useHigh-wear, high-exposure applications like decking where density and durability matter most
DurabilityNaturally dense and durable, often with a longer service life above ground
CostHigher upfront cost than treated pine
Thermally modified timber
Best useDecking and cladding-style applications wanting stability and a refined appearance
DurabilityHeat treatment improves dimensional stability and decay resistance without chemical treatment
CostHigher than treated pine, positioned as a premium option
02 · What to check before choosing
Four questions to answer before comparing species.
Ground contact or above ground?
This single question rules certain treatment classes and species in or out before appearance is even relevant — always confirm the correct treatment class for the actual application.
Exposure level
Coastal salt exposure, full sun, or sheltered positions all affect how quickly any timber weathers and how soon it needs maintenance attention.
Maintenance appetite
Some species and treatments hold their appearance with minimal upkeep; others need periodic oiling or staining to perform and look as expected over time.
Structural vs. decorative use
Structural applications (posts, retaining) prioritise treatment class and strength; decorative applications (screening, cladding) can weight appearance more heavily.
03 · Before ordering timber
Confirm these before a material is finalised.
- Confirm the correct treatment class (H3, H4, H5) for the specific application, not just a general "treated" specification.
- Match species durability to actual exposure conditions on the specific site.
- Be realistic about the maintenance schedule you'll actually commit to before choosing a higher-upkeep species.
- For structural applications, confirm timber grade meets the load requirement, not just the visual finish.
Best timber for landscaping: common questions
What does the H3/H4/H5 treatment rating actually mean?
These are hazard classes indicating what level of exposure and decay risk the treatment is rated for — broadly, H3 suits above-ground exterior use, while H4 and H5 are rated for ground contact, with H5 for more severe ground contact situations.
Is untreated hardwood a safe choice for ground contact?
Some naturally durable hardwood species perform reasonably in ground contact, but this depends on the specific species and should be confirmed rather than assumed — treated timber remains the more predictable choice for structural ground contact.
Does thermally modified timber need oiling like regular timber?
It generally needs less maintenance than untreated softwood, but manufacturers still commonly recommend periodic treatment to maintain colour, since it will silver over time like most exterior timbers if left untreated.
Sources & methodology
Designed to show its working.
Timber treatment ratings and appropriate use classes are set by New Zealand timber treatment standards. This guide is general material guidance; confirm the correct treatment class for a specific structural application with a supplier or licensed building practitioner.