"These guys know their South African native plants...and vitally where to find them," he tweeted.
Three days earlier, Bailey tweeted: "No filter, just the Drakensburg Mountains in all their 5am glory. Off plant hunting today in pursuit of some rare gladioli. Can't wait! (sic)"
The Kogelberg Botanical Society website posted a notice earlier this year announcing that the Saunders' would be speaking on gladioli in Betty's Bay in the Western Cape on January 20.
"A number of them grow in the summer rainfall regions of South Africa, and a number of them flower in midsummer," it said.
Couple only had one more plant to find
"Rod and Rachel have visited the Drakensberg four years running to try to find several species that flower in December in the mountains. As of today, they have found and photographed 164 of the South African species, and only have one left to find – Gladiolus uitenhagensis which comes from close to Port Elizabeth."
According to a website, they own the Cape Town company Silverhill Seeds, which is based in Kenilworth.
"Silverhillseeds.co.za is an independent company owned by Rod and Rachel Saunders," the company's website says.
The Pacific Bulb Society website provided details about the couple.
"Throughout much of the year they travel around South Africa collecting seeds. Rod is the former chairman of the Indigenous Bulb Association of South Africa, a first-rate photographer, and a popular speaker," it said.