David and Sue Wilson bought this block of 3000 square metres north of Toowoomba, south-east Queensland, with a goal: to indulge their passion for succulents, especially cacti. Having acquired a fascination for these dramatic, hardy species from Sue’s mother, as well as some of her showpiece plantings, they’ve devoted eight years to their horticultural mission. Today, the long rollcall of distinct plants in their large garden demonstrates the diversity and potential of these species, and their suitability for today’s water-conscious climate.

“We designed the garden this way to show people what can be done with these extraordinary plants,” explains David. “With this ongoing drought, they are an increasingly practical solution to the traditional, garden-variety flora.”

When they bought the property, the existing yard was seriously neglected, filled with overgrown, badly damaged natives and infested with weeds. It was a case of clearing the lot and designing new garden beds to fit the natural slope of the land.

“We wanted to showcase these plants as a complete garden in its own right,” says David. “We built the beds up in layers with sleepers and rock borders, then backfilled for the next level to create varying heights with as many aspects as possible. I wanted to keep the pattern fluid rather than lineal, to reflect the natural shape of the foliage.”

To a large extent, the garden design has been a process of trial and error, in terms of materials and planting. “I started off with river sandstone around the plants, but the monotone shades reduced the character of the entire garden,” reflects David.  “I vowed and declared not to do it again, and started sourcing a selection of stones in a range of colours.” The new rocks, each placed by hand, are used for mulch as much as for aesthetics: they limit water evaporation and run-off, keep down weeds and form a dynamic canvas for the succulents and cacti.

The garden is an ever-expanding case study of cross-pollination and cuttings, with close to 3000 species, sub-species and cultivars now created. “All the cacti are grown from seed and most succulents from cuttings, but we are always experimenting with growing the succulents from seed and crossing different species,” explains Sue. “It’s also interesting to watch the bees do their job and see what other hybrids nature brings.”

Cacti can also be struck from cuttings, but it takes so long to grow a beautiful, mature cactus that David and Sue refuse to strike and destroy the integrity of the parent plant. Instead, the couple maintains five greenhouses as nurseries for thousands of seedlings. Most of these are sold locally at the Cabarlah and Nanango markets.

This hands-on project has been a gradual evolution and education, with hard-learnt lessons along the way. Although the couple gleaned valuable insights from Sue’s mother, who began collecting plants and books on the species some 30 years ago, David maintains the best way to learn about succulents and cacti is to just get started and then let the plants tell you what you need to know. “I had to relearn all the different plants in terms of how they would grow in this specific garden,” he points out. “It’s a never-ending educational exercise.”

Several species now claim pride of place in the layout, including a 20-year-old Agave ferdinandi-regis, which has a 30-year lifespan and flowers just once, in spectacular fashion, before dying. Its flower stalk can grow as high as six metres from the centre of the plant. But the couple gave up having sentimental favourites years ago. As Sue remarks with a smile, “There are just too many wonderful species.”

David and Sue’s long-term commitment to the development of these intriguing species, and to educating others about them, reflects their genuine love and deep enjoyment of these plants. “Succulents and cacti are just another world,” says David, “and their limit really is the individual’s imagination.”