Our backyards have come a long way since the 1970s and 80s, when ‘scrappy native gardens’ defied belief.
For Lisa Mercer, the richest horizons are found underground, in soil profiles that support her vision for a curated native garden.
It’s one of the reasons why a tree can thrive in one backyard but remain stunted in another.
“When a developer cuts a site ready to build a home, they cut into the soil’s horizons and you end up planting in soil that would never normally support plants, almost to the bedrock,” the Queensland landscape architect said.
“You can’t just put 200mm of topsoil on it and expect a good quality garden to grow easily, you need to make sure you are recreating a natural soil profile to support small, medium and large plantings.”
Five years ago, Ms Mercer bought such a block at Helensvale on Queensland’s Gold Coast and began enriching the soil in preparation for her own native garden.
She now has native plantings around her 2023 sqm property that attract nectar feeding birds and the occasional blue banded Australian native bee.
“There’s different ways to look at native plants,” Ms Mercer said.
“A plant can be native to a region, but in the context of the nursery industry, it could be from anywhere in Australia, and then you have two native parent plants that nurseries have crossed to create a new plant, but it’s still native.
“If I went to a nursery, I might pick up a Protea from Western Australia, a Victorian Buxus and then try to grow them in Queensland, in the subtropics.
“You can force a plant to grow here and you will need fertilisers to help it thrive, but it won’t ever be as successful as in its native region.”
But that is exactly what Ms Mercer is doing on her wedge-shaped block that backs on to a creek. In fact a large part of her backyard is a native garden experiment, to help inform her work as a professional landscape architect at Burlington Brown Architects.
“The garden is my palette so I might plant the same plant in a few different places in the yard and treat it differently. I might prune one like a hedge, or leave another one natural. Put one in full sun and one in heavy shade, just to see how it responds.”
To prepare the backyard, a series of raised terraces were built using 70 basalt boulders and mulch transported to the property via a barge on the waterway.
The retaining walls were lined with a geo textile fabric and have been used to create less steep embankments for the plantings.
The garden is divided into rooms, with an upper house level and a lower creek level, although the existing land form was used as much as possible.
“There were key rooms that I wanted to frame and things I wanted to screen. I didn’t want to look out at houses and see the neighbours, so I strategically planted to create and frame outdoor rooms.
“Then once the structure was in place, I proceeded to do the understorey.”
Apart from experiments with natives from other regions, the garden has a solid foundation in plants endemic to the local area.
“My particular interest was looking for plants that enjoyed creek side or riparian contexts,” she said. “So I prioritised plants that you would naturally find alongside a creek and I used some online resources to better understand what might have been here prior to Europeans to understand the types of plants that would grow here.”
Ms Mercer grew up in the suburbs of Brisbane in the 1970s and 80s, when ‘scrappy native gardens’ defied curatorial direction.
“Contemporary landscape architects are now using sculpture and colour and form as strong cues,” Ms Mercer said. “And we’re about educating gardeners that native plants aren’t that dry scratchy scrappy look, they can be quite beautiful.
“We are drawn to form, with function and shaping, so we probably use, not hedging but formative pruning as a technique to encourage plants to do what we want as a landscape outcome.
“In my garden I try to use contrasts, I’ll use foliage that is red against foliage that is strongly green and it brings out both colours. The bark of a Water Gum or Tristaniopsis with the red berries and green foliage of the coffee bush.
“The fundamental principle of this kind of gardening is don’t be scared to use natives, but understand what you’re planting and if in doubt, get advice.”