Yggdrasil is an immense and central sacred tree in Norse mythology. In the DC Universe, it is the glorious queen of the Parliament of Trees and the home of Ratatosk on the Sphere of the Gods. It is also the planet's first plant elemental, who created the other two members; Tuuru and Eyam.
Yggdrasil was adapted by Doug Wheeler and Tom Yeates, first appearing in Swamp Thing (Volume 2) #89. (1989)