Clematis query

Never had much luck taking clematis cuttings? What the trick?

In late summer I take 8" lengths of semi-ripe stem, (maybe 3 pairs of leaves), and trim off all but the top two leaves. I leave about an inch of stem below the bottom leaf nodes and put the cuttings round the edge of a pot filled with J.Innes No 1 compost, sinking the bottom leaf nodes below the soil. Water them in, tie up in a poly bag, and leave in a warm place ( no GH so I generally bring them onto a shady windowsill). I usually put 5 or 6 to a six inch pot, and if I'm lucky one or two grow in each.

I shall try spring cuttings this year as it died back early last year.

I may try root cuttings as well - I had a macropetala that regrew from a broken piece of root when I moved it, so worth a go.