Onkaparinga River National Park
| Location | Onkaparinga River National Park, Eastern Section |
| Start/End Point | Chapel Hill Road, Blewitt Springs |
| Distance | 4 km loop |
| Time | 2 hours |
| Difficulty | Intermediate |
| Activity | Walking |
| Region | Adelaide & Adelaide Hills |
| Accommodation | Camping, mid-range and premium options — See accommodation options |
| Key Feature | Diverse remnant vegetation, heritage ruins |
A Patchwork of Soils and Stories
In the eastern section of Onkaparinga River National Park, where the suburban sprawl of Adelaide’s south gives way to the vineyards of McLaren Vale, a four-kilometre loop trail winds through one of the finest remaining pockets of remnant vegetation in the southern Adelaide region. The Hardys Scrub Hike is a walk through ecological diversity — a place where the varied soils create distinct plant communities within a compact area, each supporting its own assemblage of trees, shrubs, and wildlife. It is also a walk through human history, passing heritage-listed ruins that speak to the farming families who worked this land in the nineteenth century.
Onkaparinga River National Park protects the spectacular gorge carved by the Onkaparinga River — the longest river on the Adelaide Plains — along with significant remnant vegetation and cultural heritage sites. The park’s diverse hiking trails lead to cliff tops with views across the gorge, down to permanent rock pools, and through woodland habitats that support koalas, kangaroos, possums, echidnas, and a rich community of woodland birds.
The Walk
A Lesson in Soil and Trees
What makes Hardys Scrub botanically remarkable is the diversity of soil types within a small area, and the dramatically different plant communities each soil supports. Grey box eucalypts grow in the fertile loam or clay soils, their broad canopies creating a woodland with a distinctive character. Pink gums prefer soils with a sandy, well-drained surface and a clay or rocky base, standing tall and pale-barked in their preferred habitat. Southern cypress pine grows only in sandy loam soil, its dark, columnar form creating groves that feel ancient and still.
Walking through Hardys Scrub, these transitions are visible — you can watch the vegetation change as the trail crosses from one soil type to another, each community sharply defined by the geology beneath your feet. It is a living demonstration of how soil determines landscape, and why protecting remnant vegetation is so important in a region where most of the original plant communities have been cleared.
Heritage Ruins
Parts of the park were used as farmland for many years, and the trail passes heritage-listed huts and the ruins of houses built in the 1880s. These stone remnants, slowly being reclaimed by the bush, tell the story of the European settlers who cleared and farmed this land before its ecological significance was recognised. The contrast between the crumbling stonework and the surrounding native vegetation creates a poignant reminder of the competing pressures on the Australian landscape.
Wildlife
The diverse vegetation communities support an equally diverse wildlife population. Koalas are present in the park and may be spotted in the eucalypt canopy. Western grey kangaroos graze in the more open areas, while echidnas shuffle through the leaf litter and possums emerge at dusk. The varied woodland habitats make this an excellent area for birdwatching, with different species favouring different vegetation types throughout the walk.
Planning Your Walk
The Hardys Scrub Hike begins at Chapel Hill Road in Blewitt Springs, in the eastern section of Onkaparinga River National Park. The loop trail can be walked in either direction. The intermediate rating reflects some uneven terrain and moderate gradients. The park is easily accessible from Adelaide’s southern suburbs and makes an excellent half-day outing, particularly when combined with other trails in the Onkaparinga River National Park network.
The Hardys Scrub Hike is a compact walk with an outsized ecological story. In just four kilometres, the trail crosses soil boundaries that create dramatically different plant communities, passes ruins that speak to the land’s farming past, and moves through habitat that supports some of Adelaide’s most beloved native wildlife. It is a walk that rewards observation — a place where looking at the soil beneath your feet tells you what trees will be overhead.
Where to Stay
Planning an overnight trip? See our Clare Valley Accommodation Guide for the best places to stay near this trail.