Kendha-Ya was the name of an out-region on the planetVulcan, also known as the Dead Ocean. One part of it looked like a nigh-inhospitable wasteland, barren with steaming crater holes. The sand worm lived in this region. The Shin-Ka-Ti plant was known to grow only in this region, and nectar from that flower provided the only known cure.
The Red Plague which killed more than one million Vulcans erupted from here in the 2070s.
CaptainSpock visited the Kendha-Ya region in 2279 to retrieve a Shin-Ka-Ti plant. He estimated his probability of dying there at .57808. While removing one of the plants, he was attacked by a sand worm, which he had to kill using a hand phaser. (TOScomic: "Terminally Yours")