Embodiments describe techniques and configurations for an apparatus including a three-dimensional (3D) memory array having a plurality of strings of memory cells, where individual strings may have memory cells that correspond to different memory blocks (e.g., multiple memory blocks per string). For example, a first set of memory cells of a string may be included in a first memory block, and a second set of memory cells of the string may be included in a second memory block. The memory device may include separator wordlines disposed between wordlines associated with the first memory block and wordlines associated with the second memory block. The separator wordlines may receive different bias voltages during various operations of the memory device. Additionally, a wordline biasing scheme may be selected to program the first memory block based on whether the second memory block is programmed. Other embodiments may be described and/or claimed.