Hit the Ground Running

There are occasions in the garden when you want to cover the largest area of ground possible with the least amount of mucking around. When I was designing gardens for a living this situation occurred a lot, since I was often asked to draw up plans for new properties built either on top of a hill, or more problematically, cut into the side of one. One job in particular was memorable. The house had been built at the bottom of the tallest “battered bank” I’ve ever seen. It would have been at least 15m in vertical height, west facing, and battered at an angle of about 30 degrees. That’s a daunting amount of bank. It’s also a lot of bare subsoil on which to grow anything other than a weed.

Even though the clients weren’t raving fans of native plants, I found it really hard to overlook some of the groundcover grevilleas. The older cultivar ‘Poorinda Royal Mantle’ was my go to plant, and as far as I’m concerned, remains the pick of the lot for difficult slopes. It might be 50 years old, but continues to set the standard in terms of drought tolerance, frost tolerance, speed of growth and reliability. It’s also exceptional value for money. A single plant can cover an area of more than five metres in diameter. Plus, it’s pretty to boot.

Another standby that made its way on to the planting plan was Grevillea ‘Bronze Rambler’. This cultivar is slightly taller growing and more layered than the carpet like ‘Royal Mantle’, but in my experience it is just as tough and proves highly attractive to small birds, who use the prickly foliage for protection. ‘Gin Gin Gem’ was a third cultivar that made the cut, thanks largely to beautiful foliage that cascades down a bank like a set of green waves.

Exotics too worked well. Juniperus conferta, or shore juniper, is an outstanding plant in many regards. I love the fact that it blends really nicely with native plants, but probably exceeds many of them in terms of toughness. It is pretty much bomb proof. Hence the reason you see shore juniper in another really tough environment – the dreaded shopping centre carpark. Here, you might find it growing alongside another old toughie, Chinese star jasmine. Featuring one of the trickiest botanical names in the book, Trachelospermum jasminoides is commonly grown as a climber, but works equally well as a ground cover or even a low, table-like hedge.

There are other situations though when you need a plant that will cover a smallish area of ground to prevent weed growth or just to act as an attractive filler between bolder, more architectural plants. This is where some of the spreading clumpers (for want of a better term) come into their own.

The Toowoomba violet, Viola odorata, is as good as anything in a semi-shaded position, filling the air with it’s sweetly scented perfume in early spring. Its native cousin Viola hederacea doesn’t have the same perfume but is also an excellent plant. I once saw a big clump growing beautifully on the Springbrook plateau and after arriving home, raced out to the nursery and bought enough plants to cover the ground beneath a young camellia hedge. It worked beautifully, doing exactly what I wanted it to do – suppress weeds but in a much more attractive way than boring old mulch.

Another ground cover plant that takes my fancy is Ajuga, commonly known as bugle weed. With sufficient moisture it will grow in everything from full shade to full sun, and it will spread quite quickly to cover a decent sized area. Carolyn Robinson has used it extensively as a ground cover at Glenrock, her magnificent garden just across the border at Tenterfield. A range of cultivars exist, including ‘Jungle Beauty’ and ‘Catlin’s Giant’, and like the violets, there’s a native species – Ajuga australis.

For something a bit different but very effective as a ground cover amongst cottage-type plants I’m a big fan of some culinary herbs. Oregano in particular is really tough and will happily scramble between larger plants without overtaking them. Thyme is also good, as is common sage, salvia officinalis. The variegated cultivars, alternatively coloured purple or yellow, make a nice contrast between flowering plants and will cope with particularly hot and dry conditions.

The next time you build a house on a hill, or buy a place with steep banks, or simply want to fill in some gaps, forget about using the strappy leaved plants that are in vogue with the modern landscaping crews. Like a two-wheel-drive vehicle on a bush track, “strappies” can only achieve so much. Go for proper groundcover plants instead. They’re absolutely made for the job.

First published in the Toowoomba Chronicle 30th May 2009. Photo by Allison Steiglitz.

Tagged as: ajuga, chinese star jasmine, grevillea, ground covers, shore juniper