Tarkalea was the homeworld of the humanoid species known as the Tarkaleans.
It was also the homeworld of two avian species, the Tarkalean condor and Tarkalean hawk, as well as the source of Tarkalean tea. (DS9: "Past Prologue", "Nor the Battle to the Strong", "The Begotten", et al.) It was also the origin of the viral illness Tarkalean flu. (VOY: "Body and Soul")
In 2153, T'Pol contacted Tarkalea to inform them of the loss of their freighter and that they were attempting to do everything they could for their crewmen. (ENT: "Regeneration")
This planet was only mentioned in dialogue.