I have taken Berberis cuttings at this time of year but only because this was the only option. A customer gave me a couple of shoots of a dwarf type with scented flowers (name escapes me). I put them in a sheltered part of the garden in good soil (out of the sun) and both rooted. Just keep them moist. I put a cut off plastic bottle over them and when the new growth started, removed the screw top.