"John Smith" wrote Yes, say:- snip
Clematis
snip

Yes, but only for some cultivars. All the montanas will take very well if
you strike hardwood cuttings around Xmas and, if you do it right, you can
get a near 100% take. Same technique as you would use for the more normal
softwood cuttings and be sure to "wound" on one side, but there's no need
for bottom heat or any shading, as it's best to let the cutting break bud
naturally when Spring arrives.

Strike in a pot of grit/peat (be generous with the grit), put in the
greenhouse/cold frame or a sheltered part of the garden, keep reasonably
moist and they'll be rooted by April. Pot-up in May, then pot-on into a
2l pot in July and you can plant them out the following year

I've done the same with C. x jouiniana and it's close relative C.
heracleifolia. I have rooted the large flowered cultivars but the success
rate is nowhere near as good. I do know of one nurseryman who does all
his C. armandii cuttings on Boxing Day, but I sometimes think that this is
an excuse to retreat from the overwhelming excesses of a family Xmas.

I'd never seen this written-up and rather "discovered" the technique
whilst experimenting a few years ago and was asked to publish. When I
did, I got all sorts of comments from some nurserymen for giving away
"trade secrets". The amusing part was that they hadn't been propagating
that way either, but I subsequently found one who then switched to
propagating all his montanas that way.

- Tom.