"I grew up with roses and ever since I was given my own bit of the garden at age eight I've always been interested in plants," he said.

Roses in particular have always been David's gardening passion.

"You can get four or five flushes a year from roses – what else does that?" he said.

David's family grew grapes and other fruit as a business but David began extending his father's rose plantings of 500 bushes and selling the flowers commercially.

"I used to pull out an acre a year of the least productive vines and it all went from there," he said.

The rosebush numbers reached 3000 by 1968 and eventually 50,000 bushes covering 11 hectares.

David started selling roses in Renmark in the mid 1960s and his roses are now sold right across Australia.

The garden's custodianship is now in the hands of David's niece Anne Ruston and her husband Richard Fewster.

"I was working 17-hour days and since I was in my early 70s I was thinking I may have to sell the garden," he said. Anne offered to buy the garden, and she and Richard have built on the tourism element of the property. The garden now features an air-conditioned cafe, historic racing and classic car display and gift shop.

Thousands of people visit the garden each year.

Water restrictions pose the garden's biggest challenge, so heavy mulching is used to conserve water.

David has lectured and demonstrated flower arranging at rose conferences throughout the world – including across Australia, the United Kingdom, Canada, the US, Bermuda, South Africa, New Zealand and Europe.

His unique style of arranging displays at breakneck speed while entertaining the audience have made him a much sought-after keynote speaker.

He has been granted life membership of the National Rose Society of Australia, the Rose Society of South Australia, the Royal National Rose Society, the American Rose Society, the Indian Rose Society, Heritage Roses of Australia, Garden Clubs of Australia, the Renmark Garden Club and the Renmark Agricultural and Horticultural Society.