The process can take years and there are many that never make the cut.
"They have to be able to cope with our cold and damp conditions. There are many gaps in the garden which represent the ones that haven't made it,'' he said.
For many years the business was run from a larger property at South Kaipara Head until Prince's move to Northland in 2011.
Now 80, he has help with the process of potting up cuttings to be ready for sale.
Prince said his career in horticulture was represented in 10-year blocks.
"Every 10 years I tend to get a bit restless and want to try something new,'' he said.
He started out with subtropical fruits before getting into growing palm trees until falling in love with hibiscus flowers.
Each interest has always been in rare and unusual varieties of plants.
At one stage he had about 60 different banana varieties, 170 palm species or varieties, more than 20 sorts of casimiroa, also known as white sapote, about 30 different passionfruits and more than 40 varieties of apple.
Some of his palm trees made it up to the Kerikeri block, with special varieties continuing to grace the property, including rare varieties from Lord Howe Island.
"They have four different palm species. We have one."
Despite such exotica, his favourite palm for growing in Northland is the native nikau.
Prince said hibiscus needed warmth and shelter as well as free-draining soils.
"Northland is often described as subtropical but it's more accurately warm temperate.
"Lots of subtropical and tropical plants prefer dry winters and wet summers, whereas here it is the reverse.''
Prince said soil diseases had proved to be more of a challenge at Waipapa.
"I have lost far more plants here than in 24 years at South Kaipara,'' he said.
Buying hibiscus seed had become more competitive, with seed packets now in contested auctions against buyers from around the world.
"The prices have gone up a lot as well, from about $5 to $35 for a packet of five or six seeds,'' he said.
There were no guarantees that the seeds would grow successfully or manage to flower. As they were cross-pollinations, the seeds could produce any coloured flowers based on the parents.
A big part of the enjoyment was waiting to see what would emerge and being able to name them, he said.
"I've named them after friends, girlfriends and family as well as colourways – whatever takes my fancy. It's a lot of fun.''
Prince said once a plant started to flower for the first time and look promising, he would give it a tentative name. If they continued to do well in trials over the next year or two, he would propagate them for sale.
"They have to show me they will survive my climate outside on their own roots and that they produce worthwhile flowers in good numbers.''
Some would be rejected if the flowers were too small or if the petals in large blooms were too floppy.
"I will then graft the most promising ones on to rootstocks made from plants that are known to be vigorous in New Zealand.
"Then I can offer the resulting plants for sale with confidence. That might not happen some years,'' he said.
All plant sales, including exotic fruits, were through the company website, when and if they were available.
