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We study the thermodynamic properties of 1 S = Ising and Heisenberg ferromagnets with both bilinear and biquadratic exchange and/or uniaxial anisotropy of both easy axis/plane character. Using the meanfield (MF) approximation we evaluated the free energy enabling us to study in detail the behavior of the order parameters and the dependence of the critical point on the anisotropy. We show that in the presence of biquadratic interaction, there is a difference in the behavior between the Ising and the Heisenberg model even in the MF approximation, which is not the case for the bilinear interaction. Combining the equations of motion for Green's functions with identities particular to 1 S = , we managed to perform the random phase approximation without the decoupling of the operators at the same site, avoiding the peculiarities of the Callen -Anderson decoupling. This allowed us to improve the phase diagram for the Heisenberg model. The important result is the demonstration of the effect of anisotropy to nonvanishing of the quadrupolar order parameter at the Curie point.