  An LRS Bianchi-I space-time model is studied with constant Hubble parameter
in $f(R,T)=R+2\lambda T$ gravity. Although a single (primary) matter source is
considered, an additional matter appears due to the coupling between matter and
$f(R,T)$ gravity. The constraints are obtained for a realistic cosmological
scenario, i.e., one obeying the null and weak energy conditions. The solutions
are also extended to the case of a scalar field (normal or phantom) model, and
it is found that the model is consistent with a phantom scalar field only. The
coupled matter also acts as phantom matter. The study shows that if one expects
an accelerating universe from an anisotropic model, then the solutions become
physically relevant only at late times when the universe enters into an
accelerated phase. Placing some observational bounds on the present equation of
state of dark energy, $\omega_0$, the behavior of $\omega(z)$ is depicted,
which shows that the phantom field has started dominating very recently,
somewhere between $0.2\lesssim z\lesssim0.5$.
