Grafting Arborvitae . On most conifers, make a thin slice or wound on one side of the cutting. Loosen some of the roots in the root ball. Thuja ‘Green Giant’ Evergreen Trees Buying & Growing Guide from www.trees.com Grafting hinoki on thuja (arborvitae) part 2. Place the sand in a bucket. Many people think that the foliage of thuja is untameable and unsuitable for bonsai.