This model is from DynaSCAPE Software's Sketch3D download site, a huge online database of landscape components for SketchUp. This model is one of the FREE models offered on the site for anyone to use. This model is made up of full 3D leaves and flowers with a poly count of just over 760.
Check out the huge collection of plants, garden structures, pools, ponds etc. at DynaSCAPE.com. You will also find textures and plugins created specifically for landscape modeling using SketchUp.