A chroma component block vector is initialized using one of a neighboring or collocated luma block vector when current picture referencing mode is used and when dual tree is enabled. In a first embodiment, if a collocated luminance block is not coded in current picture reference mode, a luma vector from a left chroma subblock is used. When the left chroma subblock is not coded in current picture reference mode, a luma vector from the above chroma subblock is used, and if that is not available, a default vector is used. In a second embodiment, a collocated luma block partition is used to derive a chroma block vector.