Laboratory experiments have been conducted on anisotropic slate specimens to study the behavior of hydraulic fractures (HFs) when encountering discontinuities. The experiments target specific propagation regimes, including toughness-dominated, lag-viscosity-dominated, and transitional regimes, to examine the influence of rock discontinuities on HF growth paths. Our experimental observations reveal that planar HF propagation is favored in the transitional and lag-viscosity-dominated regimes, where HFs exhibit a greater tendency to cross rock discontinuities. In contrast, a significant influence of discontinuity planes is observed in the toughness-dominated experiments, leading to HF diversion or arrest of the HF. The complexity of fracture paths is found to be closely tied to a dimensionless toughness parameter derived from scaling relations. This study highlights the pivotal role of hydromechanical characteristics in shaping complex HF patterns in anisotropic rocks with pre-existing discontinuities.