Warmth would probably help but if its too warm, instead of growing roots, it will grow leaves like a cut flower and then will never root. What will really help is spring.
All my propagation books says hardwood cuttings taken in late summer root easily without any special treatment. But... Is there a leaf node or two under the soil? The usual way of taking cuttings is a stem with at least 3 nodes (more is better), one up and the rest below ground. If there are no leaf nodes, it make not root. No, not a good time to check. It will root or rot so be patient.
