What Should I Plant on a Retaining Wall? Best Plants for Australian Gardens
There is a very specific moment after building a retaining wall.
You stand back.
Admire the lovely new wall.
Feel quite pleased with yourself.
And then realise...
you've basically built a very expensive backdrop for dirt.
Now what?
Retaining walls are one of those areas where the right plants can completely transform a garden.
Get it right and the wall disappears into the landscape.
Plants spill over the edge.
Grasses soften all those hard lines.
Groundcovers knit everything together.
Get it wrong and you end up with a row of plants sitting awkwardly along the top like they're waiting for a bus.
So before you start planting, there's one question worth asking:
What do you actually want the plants to do?
Because plants on and around retaining walls can have very different jobs.
Do You Want to Hide the Wall or Show It Off?
This changes everything.
If you've got a beautiful sandstone wall, you probably don't want to bury the entire thing under foliage.
You might want occasional plants cascading over the edge while leaving sections of stone visible.
Got a fairly ordinary concrete retaining wall?
Different story.
Release the groundcovers.
Think about the finished effect before choosing the plants.
Do you want:
- plants spilling down the face?
- soft grasses sitting along the top?
- a low hedge behind it?
- mass planting?
- flowers?
- something incredibly simple?
Once you know the job, choosing plants gets much easier.
1. Scaevola Purple Fusion™ — Let It Spill
This is exactly where a spreading groundcover earns its keep.
Scaevola Purple Fusion™ stays relatively low but can spread broadly, with purple fan-shaped flowers bringing colour through the planting.
Along the top of a suitable retaining wall, that spreading habit can soften the edge and allow foliage to move over the wall rather than everything stopping abruptly at the top.
And that's one of the secrets to making retaining walls look established.
You need something to break the line.
Otherwise you've got:
Wall.
Soil.
Plant.
Wall.
Soil.
Plant.
Very polite.
Very organised.
Slightly council car park.
Let something spill.
2. Aussie Rambler™ Carpobrotus — When the Spot Is Tough
Hot wall.
Full sun.
Reflected heat.
Soil that seems to dry out approximately eleven seconds after you've watered it.
This isn't necessarily the place for something delicate.
Aussie Rambler™ Carpobrotus is a spreading Australian native groundcover suited to tough landscape situations where broad coverage and a low habit are useful.
Its fleshy foliage also gives you a completely different texture from grasses and shrubs.
That's important.
A good retaining-wall garden doesn't need twelve different plants.
But it does benefit from different shapes.
3. Aussie Hedge Bush™ Rhagodia — The Silver One
This is where things get interesting.
Aussie Hedge Bush™ Rhagodia spinescens brings that beautiful silver-grey foliage that can completely change a planting scheme.
Against concrete, stone, timber or darker foliage?
Magic.
It's also Australian native saltbush, so you're getting something that feels distinctly at home in a tougher Australian landscape rather than looking overly manicured.
Use it where its mature size and site requirements suit the space.
And don't underestimate silver foliage.
Sometimes one change in foliage colour does more for a garden than adding another five flowering plants.
4. Cenchrus Nafray® — Bring Some Movement
Retaining walls contain a lot of hard lines.
Straight edges.
Posts.
Concrete.
Blocks.
Stone.
Which is exactly why grasses can work so beautifully around them.
Nafray® brings movement.
When the wind catches the foliage, suddenly the garden doesn't feel quite so rigid.
Repeated along a longer wall, ornamental grasses can create rhythm without needing every plant to be different.
And if you've got a 20-metre retaining wall, please don't feel obliged to invent 20 different planting ideas.
Repeat things.
Your garden will thank you.
5. Lomandra Tanika® — The Reliable Backbone
Sometimes you need the plant that simply makes everything else work.
That's Tanika® Lomandra.
Fine, arching foliage.
Movement.
Evergreen structure.
A shape that works brilliantly with hard landscaping.
Rather than making every plant along the retaining wall a feature, use reliable structural plants repeatedly and let a smaller number of flowering or spreading plants provide the excitement.
Tanika is particularly useful when you're trying to make a new landscape feel cohesive rather than like a collection of things you happened to like at the nursery.
6. Little Jess™ Improved Dianella — When You Need Something Smaller
If Lomandra feels too large for the space, a compact Dianella can give you the same sort of strappy movement at a different scale.
Little Jess™ Improved Dianella works particularly well repeated through landscape planting.
And this is where thinking in layers helps.
You might have:
A larger structural plant.
Little Jess repeated through the middle.
Purple Fusion spilling over the front.
Suddenly...
You've only used three varieties.
But the garden has height, movement, flowers, foliage contrast and ground coverage.
That's design.
Not buying one of everything.
What About the Bottom of the Retaining Wall?
Don't forget this bit.
People spend enormous amounts of time designing the planting along the top...
Then leave the bottom completely naked.
Depending on the space available, planting at the base can make the wall feel much more integrated into the garden.
Groundcovers can soften the junction between the wall and the ground.
Strappy plants can break up long expanses.
Shrubs can provide structure.
You don't necessarily need plants above AND below the entire wall.
Sometimes strategically planting both levels creates a much more natural result.
Watch the Drainage
This matters enormously.
Retaining walls and drainage go hand in hand.
Some areas around walls can become extremely dry.
Others can remain wetter because of how water moves through the site.
So don't assume every metre of the wall has identical conditions.
Look for:
- where water drains
- where runoff collects
- whether the soil dries quickly
- whether the wall creates reflected heat
- how much sun the area receives
Then choose plants accordingly.
A beautiful plant in the wrong conditions is still the wrong plant.
Don't Plant Everything Right on the Edge
We know.
You want the wall covered immediately.
But remember what those innocent little plants are going to become.
Check mature width.
Allow space.
And think about where the centre of the mature plant will eventually sit.
Planting too close to an edge can leave larger plants awkwardly hanging over the wall or competing for limited soil.
The little tube you're planting today is not the plant you're designing for.
Design for the adult.
How Far Apart Should Retaining-Wall Plants Be?
There isn't one universal retaining-wall spacing.
It depends on:
- mature plant width
- whether you're mass planting
- whether you want plants to touch
- how quickly you want coverage
- whether you're alternating varieties
For example, a spreading groundcover and a compact Dianella shouldn't automatically be planted at the same spacing.
Check the recommended planting rate for the individual variety rather than using one measurement for everything.
This is also where a plant spacing calculator can make planning a long wall considerably easier.
One Plant or Several?
For a small wall?
One repeated plant can look spectacular.
For a longer wall, I'd usually think in groups, not alternation.
This:
AAA BBBBB AAA BBBBB AAA
can often look much stronger than:
A B A B A B A B A B
Why?
Because your eye reads masses.
Groups give each plant enough visual weight to actually make an impact.
And they stop a long retaining wall looking like someone planted it using Morse code.
A Simple Retaining-Wall Planting Formula
If you're completely stuck, start here.
Structure
Choose one reliable plant to repeat.
Think Tanika®, Little Jess™ Improved or Nafray®, depending on the conditions and scale.
Contrast
Add something with a different foliage colour or shape.
Aussie Hedge Bush™ Rhagodia can bring silver foliage into the mix.
Spill
Finish with a spreading groundcover such as Purple Fusion™ or Aussie Rambler™ where suitable.
That's it.
Three jobs.
Three plant types.
Repeat.
You can create an incredibly sophisticated landscape without needing an encyclopaedia of plants.
Frequently Asked Questions
What are the best plants for the top of a retaining wall?
Plants with spreading, cascading or soft foliage can work beautifully along retaining-wall edges, provided they're suited to the site's sun, soil, drainage and climate. Groundcovers, compact grasses, Lomandra and Dianella are all worth considering depending on the conditions.
What plants will cascade over a retaining wall?
Low-spreading groundcovers such as Scaevola Purple Fusion™ and Aussie Rambler™ Carpobrotus can be useful where a trailing or spreading effect is wanted and the growing conditions suit the plant.
What can I plant along a long retaining wall?
Rather than using many different varieties, repeat groups of a small number of plants. Combining structural plants, contrasting foliage and spreading groundcovers can make a long wall feel cohesive.
Can I plant Lomandra along a retaining wall?
Yes, Lomandra can be very effective around retaining walls where the particular variety suits the available space and growing conditions. Check mature dimensions before planting.
How many plants do I need for a 20-metre retaining wall?
That depends entirely on the varieties selected and their recommended spacing. Calculate each planting group separately based on its mature size and planting rate rather than dividing the wall by one universal spacing.
Before You Buy Anything...
Go and stand in front of the wall.
Don't think about plants yet.
Ask:
What does this wall need?
Does it need softening?
Coverage?
Movement?
Colour?
Height?
Something cascading?
Once you know the job...
Then choose the plant.
Because the best retaining-wall planting doesn't make you think:
"What lovely plants."
It makes you forget there was ever an ugly bloody wall there in the first place. 🌿