His 24 palm trees, some about two metres tall, take pride of place alongside ferns and yuccas.
Other notable features are his rare black-stemmed banana plant and ginger plants.
The garden is his pride and joy – and haven.
Tim, aged 71, said he could be found in there most days, ‘just mucking about’.
“It’s a lovely place to sit,” he said.
“There’s always something to do. Weeds need to be pulled and dead leaves cut from trees to improve their appearance.”
But the former high-level fencer, of Caxton Road, Woodlands, says other keen gardeners can grow similar species in their cold Yorkshire backyards.
Tim, a semi-retired business consultant, and his partner Jane love the space though Jane is less keen on the gardening side of things.
“There are debates on how many plants I’ve got and how many are on her side,” he said.
While most of the garden’s features are easy on the eye, there are a couple which are unforgiving if you come into contact with them.
Tim has a danger sign installed, warning visitors to be wary of the trithrinax campestris, otherwise known as the caranday palm.
The palm, native to Argentina and Uruguay, has serious spikes and razor-sharp leaves.
“It’s the most dangerous palm tree there is,” Tim said.
He added he was considering opening the garden up to visitors under the National Garden Scheme. Visitors’ money would go to charity.
He is also keen to pass on his knowledge of exotic gardening to Doncastrians.
The keen sportsman was forced to make a choice between training hard with the British Olympic fencing squad or a career in management in the mid 1970s.
The latter meant he had to give up his Saturdays at the headquarters in London, but Tim said it was the obvious choice to make.
The London lad moved further north, settling in Rutland and Worksop before moving to Doncaster about 10 years ago.
Tim said space issues ensure he won’t add to his garden anytime soon.
“I don’t think I’ve got any more room,” he said.
“The garden is packed. I don’t think I could get anything else in.”
His advice for anyone looking to branch out into exotic plants is simple.
“Know your subject,” he said. “Plenty of his palm trees could survive the colder climates like Yorkshire’s.
“Some grown in the Himalayas, and have snow on them. Anybody can grow banana plants and yuccas. They’re hardy.”
Time, patience and dedication is required and many must be moved indoors during the colder months after being lifted from the garden.
The ones left outside are wrapped in hessian for protection from the South Yorkshire winter.
“They need care, no question,” Tim said.