  ``Bonsai'' Hopf algebras, introduced here, are generalizations of
Connes-Kreimer Hopf algebras, which are motivated by Feynman diagrams and
renormalization. We show that we can find operad structure on the set of
bonsais. We introduce a new differential on these bonsai Hopf algebras, which
is inspired by the tree differential. The cohomologies of these are computed
here, and the relationship of this differential with the appending operation
$*$ of Connes-Kreimer Hopf algebras is investigated.
