"The Green Team" is a cool collection of Google Earth greenery. Use it for inspiration and, as collector Ghaleb fawzi puts it, "to encourage ... beauty and [enhanced realism]" (in Google Earth).
3D modeler Aerilius has created a collection of beautiful and low-poly Google Earth entourage. Plant-making tips are included (eliminate pesky white halos around PNG textures!)
Modeler KangaroOz 3D has curated this collection of Google Earth trees as well. I have also begun a new collection called Park and Recreation. "Arboleda del Kiosko de Polvoranca" (above) by J.A. Alvarez