Vidumarh was the last of Vidugavia's three sons. He was a great warrior and adventurer. It was Vidumarh who went with Saruman as to find out what became of the Entwives. Eventually after being brought past the Sea of Rhun, they found a small colony of the Entwives still living in the Eryn Rhûn. Having been tracked and found by the Blue Wizards--the remaining Entwives products and teachings about plantlife lived on. This was discovered and used by the Northmen to create a place of abundance with the Wizards help.
The Entwives in a sense, helped the Kingdom of Rhovanion and Gondor establish a bountiful agricultural area that would come to be known as Dorwinion. This area would survive and would become a coveted area for the resources that it produced.
Vidumarh's line eventually sought a kingdom of their own and it was a descendant of his line that established the city of Dale.