Catalysis of the reaction: S-adenosyl-L-methionine + histone H3 L-lysine (position 36) = S-adenosyl-L-homocysteine + histone H3 N6-methyl-L-lysine (position 36). This reaction is the addition of a methyl group to the lysine residue at position 36 of the histone H3 protein.
histone-H3K36 methyltransferase activity