Supposedly it's The Garden that Ex Nihilo created.
https://marvel.fandom.com/wiki/Garden_(Mars)
The Garden was a region of Mars that was terraformed by Ex Nihilo to create an atmosphere capable of sustaining vegetation.[2]
Years after the Gardener's death, the locale was repurposed by Armor, who planted Flowers of Krakoa there at the behest of Xavier to create a Krakoan Habitat, a diplomatic biome interconnected to Krakoa's collective consciousness,[3] that was rechristened the Red Farm.[1]