  Understanding orbital ordered (OO) Mott insulating states lies at the heart
of a consistent resolution of the colossal magneto-resistance (CMR) observed in
manganites, where its melting induces a low-$T$ insulator-metal transition for
$0.25 \le x\le 0.45$. Motivated thereby, we study the OO states in a planar
model for bilayer manganites using DMFT and finite-size diagonalisation
methods. We derive the correct OO ground states observed in manganites for
$x=0,{1/2},{2/3},{3/4}$ in exact agreement with observations, including the
charge-orbital-magnetic ordered stripe phases for $x>{1/2}$. These OO states
are {\it exactly} shown to be associated with an ``alloy'' ordering of the
$d_{3x^{2}-r^{2}}/d_{3y^{2}-r^{2}}$ orbitals on each $Mn^{3+}$ site.
