I am an experienced gardener - and very experienced when it comes to killing Clematis. I have always had a less-than-successful record with Clematis. I would say that about 50% of the Clematis I have planted over the years have not survived their second year, regardless of in which part of the world I was gardening. I read and follow all the advice...trying to find an appropriate place, shading roots, planting a bit deep...to no avail.

Now, in the two years I have gardened here I have planted four Clematis and, true to form, two have survived.
I have planted and killed an unremembered variety as well as a lovely Clematis flammula triternata rubromarginata (which I liked well enough to try again). The two survivors have been Clematis texensis "Princess Diana" which I've grown in two other gardens and have always liked (it is in its second season now, has grown significantly and looks quite happy twining in with a Mdme. Alfred Carriere rose). As well as a recently planted and seemingly flourishing -having tripled in size in the two months since being planted- Clematis Blekitney Aniol (Blue Angel).

To my question -
Plants here are very expensive when compared to the US and it is often difficult to find anything slightly unusual. So, if you want something specific that might not be available at our version of a 'big box' nursery you expect to pay perhaps 15 - 20 euros for a 4" pot specimen - really, it's the comparative cost that seems high.

I recently purchased a Clematis tangutica "Bill McKenzie" from an online seller in Poland. It arrived yesterday and, as expected, is a very small (approximately 4" pot with 12" growth) but otherwise reasonably healthy specimen. Those of you who have more experience at growing (rather than killing) Clematis - do you suggest as I suspect, that I pot it up to something like a 1 gallon pot and grow it on for a season to bulk out with a season of coddling rather than planting it directly now?

Thanks for your suggestions.

Yes, I would put it in a 1 gal and baby it for a couple of years. Sometimes liners sold with a very good root system and it is OK to plant them directly in the ground but I usually grow them in a pot anyway. The bigger the plant that goes to the ground the better outcome. I never had failure with clematises in a 5 gal pot. Little liners die on me when I can not keep up with watering. They usually holding on till fall and even look good but fail to sprout next year. So make sure your baby is getting enough water during the summer heat as 1 gal pot can dry out very fast.

too, I always pot them up if they are in small containers, if in 1 gallons and on the small size, I will pot up to the next size and they will stay there on average 1-2 years before committing them to the ground. Once planted, I add a layer of compost about twice a year.

I planted a number of rooted cutting or plug-size clematis out in the landscape last fall, as nice and deep as they could go in the newly raised bed, so that they wouldn't frost-heave out of the soil over the winter and could establish themselves really well before the summer drought hits. They have been growing out well this spring! I am pleased to have them getting established.

I have also overwintered them in pots, and have a few still to plant in the landscape, but at this late date I think it's too close to summer to plant in any place that won't get regularly watered. So if you want to plant it where it won't be summer-watered, I'd keep it in a pot that you can coddle till fall... and plant then. But if you want to plant it in a place that won't have summer drought - I imagine you could plant it anytime.

By the way, what kind of soil are you planting in? Is it possible the clematis have been getting too wet over your winters? I don't think they take well to being waterlogged (or too dry), and they can break easily when small, but I'm not sure of any other reason they would be difficult to grow. Planting deep is good, multiple growing nodes under the soil to better establish the plant can actually be very important; they'll grow up from just under the ground like a perennial.