Coastal planting: what survives salt and wind - Plant Drop

Coastal planting: what survives salt and wind

A coastal block is not one growing environment. It is two or three, stacked up inside twenty metres. Most coastal jobs fail because one species was chosen for the whole site, and the row facing the water burned out inside two summers while the same plant behind the house did fine.

The fix is a planting order: a tough first line that takes the hit, and everything you actually want to look at behind it.

Why the first row shelters everything behind it

Salt arrives as aerosol: fine droplets carried inland on wind, deposited on leaf surfaces, then concentrated as the water evaporates off them. Deposition drops away sharply with distance and with anything solid in the way. A row of dense, salt tolerant foliage strips a large share of the airborne salt out of the wind and slows the wind itself, which is why the second row is a much easier place to plant.

A permeable living windbreak also beats a solid fence, which creates turbulence and a damaging downdraught on its lee side. And the front row is chosen for survival, not looks: pick a compromise species there because someone liked the flowers, and when it thins out the shelter goes with it and the second line starts burning too.

Reading your own site

  • Front line. Direct, unfiltered spray and wind off the water: a dune face, a headland, an exposed fence line, a seaward boundary.
  • Second line. Behind that first row, a dune, a building or existing vegetation. Still gets salt on strong onshore days, but filtered.
  • Sheltered. Courtyards and the inland side of the house, which on many blocks behave like a normal suburban garden.

Walk it on a windy day and note which side of the existing vegetation is brown.

Front line plants that hold up

Westringia

Coastal rosemary grows naturally on exposed New South Wales headlands, which tells you most of what you need to know. It takes salt spray, sand, wind and hard clipping, stays dense to the ground, and holds a formal hedge line better than most other natives. Our westringia range runs from compact forms for low borders to taller selections for a chest height windbreak. Plant it lean: rich soil and heavy feeding make it soft and open, the opposite of what the front row needs.

Banksia integrifolia

Coast banksia grows on foredunes along much of the eastern seaboard and is one of the few trees that will stand in front of everything else and keep going. It handles sand, salt laden wind and poor soil, feeds nectar birds, and on a fully exposed site leans away from the wind, which reads as character rather than damage. As a member of the Proteaceae it is sensitive to phosphorus, so use a low phosphorus native fertiliser and keep lawn feed off the root zone. Find it in the native plant range.

Acronychia imperforata

Beach acronychia is a dense, glossy leaved small tree from the subtropical and tropical coast, and the pick where you want a screen with a rainforest look on an exposed site. The leaf is thick and waxy, exactly the type that copes with aerosol salt. It suits coastal Queensland and northern New South Wales, not cold sites or frost pockets; further south, use westringia or coast banksia instead.

Metrosideros

Pohutukawa and its relatives evolved on rocky New Zealand coastlines and handle direct spray about as well as anything you can plant. The leaf is leathery, it takes pruning, and it can be run as a large shrub, a clipped screen or a single trunked tree. It is slow for the first two seasons and dislikes frost while young, so give it drainage and expect little height early on.

Pandanus

Coastal pandanus is the signature plant of the northern New South Wales and Queensland beachfront, growing in almost pure sand with spray over it. It is slow and architectural, and works as a feature or loose group rather than a screen: it does not knit into a hedge. Two cautions: it wants warmth and will not perform in cold southern gardens, and along parts of the south east Queensland coast pandanus have been hit by a planthopper causing crown dieback, so watch the new growth.

Second line: where the range opens up

Behind an established front row the palette widens a long way:

On a boundary job, take the second line from our privacy screening range and keep the seaward row to the front line species above.

What not to put in the front row

Do not plant Japanese maples, camellias, magnolias, citrus, silver birch or coral bells where they take unfiltered onshore wind. Thin or soft leaves, plus a fine branch structure in the maples and birch, means they scorch and shred rather than harden off. All of them work once they sit properly behind shelter, which is a different sentence to calling them coastal plants.

Spacing a coastal screen

Front line rows go in tighter than the same species would inland, because you want closure quickly and have to allow for losses.

Role Typical planting In row spacing
Clipped front line hedge Westringia 600 to 800mm
Informal front line screen Metrosideros, Acronychia imperforata 1.5 to 2m
Shelter tree row Banksia integrifolia 3 to 4m
Feature group Pandanus 2.5 to 3m, in odd numbered groups
Second line screen Lilly pilly and similar 1 to 1.5m

Use the upper end of each range with larger stock.

Salt burn: what it looks like

  • Browning starts at leaf tips and margins and works inward, not as spots across the leaf.
  • The damage is one sided: the windward face burns, the sheltered side stays green.
  • The newest, most exposed growth goes first, because it has not hardened off.
  • It appears in a step after a blow, not gradually: a run of strong onshore days shows up as damage within about a week.
  • Long exposure gives trees flagged growth: seaward branches stunted or dead, the crown pushed inland.

Salt in the soil looks different: scorch appears evenly over the plant, on older leaves first, with no windward bias. That is a drainage and irrigation water problem, so if a plant browns uniformly, stop blaming the wind and check the water.

On a tolerant species most salt burn is cosmetic and worth leaving. Damaged foliage still shelters the growth points behind it, and the plant pushes through it in the next flush.

Establishing plants in sand and wind

  • Plant smaller on the front line. Advanced stock in an exposed row gets rocked, never knits its root plate into the sand, and sits still for two years while smaller stock overtakes it. Save the advanced trees and semi advanced trees for the sheltered side, where the instant effect is actually visible.
  • Shelter the first two seasons. Temporary shadecloth on star pickets along the windward side, at about plant height, is the highest value hour you will spend on an exposed job.
  • Stake wide and low. Two or three stakes with broad webbing, allowing some movement, builds trunk strength. Rigid staking gives you a plant that falls over the day the stakes come out.
  • Rinse after a blow. A fresh water wash over the foliage after a salt laden storm removes deposits before they concentrate.
  • Mulch, but feed lean. Coarse mulch to hold moisture in sand, yes. Heavy nitrogen, no. Soft, sappy growth is what burns.

Planning the order

Measure the run and divide by your spacing before pricing, and count the front line first, since that row is fixed by what survives in it. To match an existing planting, browse shop all plants. We deliver farm direct to Queensland, New South Wales, Victoria, South Australia, the ACT and Western Australia for a flat $99 per order on a $399 minimum, so a full screen travels on one delivery fee.

Plants featured in this guide

Everything below is currently available farm-direct, with flat $99 delivery in QLD, NSW, VIC, SA, ACT and WA and a $399 minimum order.

Browse the full range: Westringia · Paperbark · Indian Hawthorn

Related ranges: Tea tree and leptospermum, Banksias, New Zealand Christmas bush.

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