  The existence of light, fundamental bosonic fields is an attractive
possibility that can be tested via black hole observations. We study the effect
of a tidal field -- caused by a companion star or black hole -- on the
evolution of superradiant scalar-field states around spinning black holes. For
small tidal fields, the superradiant "cloud" puffs up by transitioning to
excited states and acquires a new spatial distribution through transitions to
higher multipoles, establishing new equilibrium configurations.For large tidal
fields the scalar condensates are disrupted; we determine numerically the
critical tidal moments for this to happen and find good agreement with
Newtonian estimates. We show that the impact of tides can be relevant for known
black-hole systems such as the one at the center of our galaxy or the Cygnus
X-1 system. The companion of Cygnus X-1, for example, will disrupt possible
scalar structures around the BH for gravitational couplings as large as
$M\mu\sim 2\times 10^{-3}$.
