For 16 generations, master gardeners in this one family have dedicated their lives to preserving one of the nation's most cherished – and highly sought-out – symbols.

Each spring during sakura (cherry blossom) season, the Ninna-ji and Daikaku-ji temples in Kyoto's leafy Ukyo ward are overwhelmed by busloads of tourists who come to snap photos of the temples' blooming cherry trees. But little do they know that only a few kilometres away, there's a secret sakura garden hiding in plain sight.

This 1.5-hectare public plot, known as the Sano family garden, is an oasis of calm; found just off an unassuming street near traditional wooden machiya townhouses. But this isn't just any ordinary cherry blossom tree grove; it's also the domain of 97-year-old Tōemon Sano: Japan's most renowned sakuramori (cherry blossom guardian).

For more than a millennium, Japanese people have admired the delicate sakura petals as a symbol of transience and beauty. Today, this national pastime has blossomed into an international obsession, with millions of tourists from across the world descending on Japan to sip seasonal sakura-themed Starbucks drinks and participate in hanami (cherry blossom viewing) picnics and festivals from March to May. But while the world waits with bated breath for the cotton candy-coloured blossoms to burst each spring, one of the most important and least understood roles in the trees' maintenance lies with their behind-the-scenes caretakers.

According to Naoko Abe, cherry blossom expert and author of The Sakura Obsession, skilled sakura arborists have existed in Japan since time immemorial. But thanks to the popularity of the 1970s novel Sakuramori about a sakura-infatuated tree expert, communities began bestowing this title to deserving specialists in the years that followed. Typically a professional gardener or tree surgeon, a sakuramori is a combination of Lorax, botanist and spiritual guide dedicated to studying sakura and promoting their preservation.

As Asada Nobuyuki, the secretary general of the Japan Sakura Association, explained, there are roughly 100 sakuramori in Japan today, but one stands out. "It can be said that Tōemon Sano is most deserving of the title sakuramori," said Nobuyuki, crediting the breadth of Sano's long, productive career and his family's generational wisdom.

On a Friday morning earlier this month, I crunched through gravel at this historic sanctuary to meet Sano himself. He is the 16th generation in a distinguished line of farmers who began cultivating the nearby land (known for its late-blooming dwarf cherry trees) in the mid-1600s. When his father died in 1981, he assumed the first name Tōemon, per family tradition, and took the reins of Uetō Zōen, the landscaping firm his family started in 1832 that is headquartered in the garden.

For more than 80 years,Sano has utilised his specialised knowledge to steward the survival of sakura trees in gardens throughout Japan and the world – including at the Isamu Noguchi-designed Japanese garden at the Unesco headquarters in Paris. Sakura Taikan, his most famous book, is the definitive tome on the trees and the culmination of research begun by his grandfather during the Taishō period (1912–1926).

But just before our visit, the nonagenarian became ill and was rushed to hospital. Still, he arranged for me to meet his son, Shinichi Sano, who oversees operations at Uetō Zōen and who will one day succeed his father and carry on the family legacy as the next Tōemon and sakuramori.

As we strolled through the garden, Shinichi paused at an umbrella-like shidarezakura........

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