Plants for Retaining Walls

Top of wall, face or base: choose by position

The bed along the top of a wall drains fast, heats up and dries out, so it favours drought tolerant spillers. Cousin It (Casuarina glauca 'Cousin It') hugs the ground at about 30cm high and weeps over an edge in a dense green curtain, trailing silver dichondra (Dichondra argentea) spills its stems well over a metre down the face, and creeping boobialla spreads 2m wide while staying ankle height. Star jasmine works both ways, spilling over the face or covering the bank behind. At the base, upright clumpers hide the footing: lomandra, liriope and blueberry lily give strappy structure without hiding the stonework entirely.

Matching retaining wall plants to climate and exposure

Cousin It, creeping boobialla, seaside daisy, the lomandras and Evergreen Giant liriope all take frost as well as coastal wind, so they suit almost every region; many are Australian natives bred for exactly this work. In frost free and near frost free gardens, pigface adds succulent colour along a hot edge and a trained bougainvillea turns a high wall into a curtain of colour. Hardenbergia 'Sea of Purple' scrambles over a bank or climbs to around 2m and takes frost in its stride.

Spacing and how many plants you need

• Spillers along the edge. Cousin It and creeping boobialla at 1m apart, silver dichondra at 40cm, pigface at 60cm. Set each plant 20cm to 30cm back from the lip so the roots are not baking against the face.
• Binding the slope above. Creeping boobialla or Grevillea 'Forest Rambler' at 1m centres knit soil together quickly.
• The base row. Tanika lomandra at 60cm, Lime Tuff lomandra at 50cm, Evergreen Giant liriope at 40cm, blueberry lily at 50cm.

On the slope itself, plant into a small level shelf cut into the face so water soaks in beside each plant instead of running straight off.

Getting plants established on a dry bank

The first summer decides everything here, because raised beds and slopes shed water. Soak deeply twice a week, mulch with a chunky bark that will not wash downhill, and feed lightly in spring. A cheap dripline along the top bed pays for itself in the first heatwave. Once roots are down, most of this collection, and everything in our low maintenance groundcover range, looks after itself.

Common questions

Will these plants damage the wall?

No. The groundcovers and strappy plants here hold soil with fibrous roots rather than structural ones. The plants to keep away from any retaining wall are large trees. Climbing fig is the one to watch in this collection: it is safe on solid masonry but its clinging roots mark render and painted surfaces.

How quickly will something spill over the edge?

Silver dichondra, creeping boobialla and pigface are the quick ones, draping the face within a season or two. Cousin It takes longer but builds a thicker, more permanent curtain.

What suits the shaded strip at the foot of a high wall?

Evergreen Giant liriope handles the part shade a south facing wall casts, flowering purple in the process. Where the sun rarely lands at all, pick shade tolerant groundcovers rather than the sun loving spillers, which grow sparse and leggy without light.

Can I use climbers to cover the wall itself?

Yes, on the right surface. Self clingers like climbing fig suit bare block and brick, while star jasmine on wires works on any wall. Our climbing plants range covers both kinds.