You don't say where you are (see below for directions as to how to add this to your profile so it pops up with your name on every posting) so this is a bit of a guess . . .

Your potting medium looks really wet. Clematis don't like soggy soil, so it may be having issues with that. Particularly with no working leaves it needs to be much drier and have better drainage. I'd knock it out of the pot and take a look at the roots. If they are whitish or yellowish, it will be fine. Replant in better-draining medium, or better yet, get the garden ready and plant in the garden with the base of the stems about 4" below ground level. If the roots are brown and smooshy, they have rotted and the plant is dead.

Have you had a frost yet? Frost will kill the leaves.

The leaves look a bit whitish. Powdery mildew will kill off leaves of a stressed plant. Cut back vines and remove all leaves. Then put it in a sunny spot, not letting it dry out completely (test several inches below surface with your finger), but preventing the soil from being soggy.

It looks like there may be a tiny pip of green at the base. If that is the case, cut back the dead vines (you should do that, regardless) and then put it in a sunny spot, not letting it dry out completely (test several inches below surface with your finger), but preventing the soil from being soggy.

If you are in a cold area (below zone 6 or so) Piilu will need winter protection in a pot. Either put in an unheated garage if it will stay warmer there than outside or wrap pot in bubble wrap and put mulch on surface or pile bags of leaves around the pot after there has been a hard freeze and temps will stay colder.

To add location info to your postings:

Go to Your Houzz in upper right of every page, click Edit Profile, and on the left side click advanced settings. Well down the advanced settings page is a blank labeled Climate Zone for Garden Forums along with a link to find your zone.

If you add info on your state or the nearest large city you will get even better information since zone only relates to average coldest winter temperatures.

Then return to the top of the page and click Done Editing.

Hi thanks for the reply I looked at the roots and they are yellow/white there does seem to be a bit of green on the base so hopefully it's just not liking the pot, going to plant it out as you said and prune the leaves back. We haven't had frost but it's been very cold 3-4c and damp during the night and sunny and about 15c during the day

Hi Craig.

You could just have wilt on your clematis. It's quite common, especially when a plant is newly bought and goes into different conditions to that of a nursery. It is unlikely to be powdery mildew, as most clematis (apart from Rooguchi and a few other prune 3's) are very resistant to mildew.

The best thing you can do, regardless of the cause of your plant looking dead, is to cut the stem down to just above the first node above soil level. This will encourage root growth and new stems should appear within a few weeks again. Your roots still sound as though they are fine (they look like yellow boot straps, so if they're yellow, then they're fine. If they go black and stringy, then you have root-rot).

Your second post says your area is getting cold, so your Piilu might just be in dormancy. Apart from evergreen varieties, all clematis go into dormancy in winter and look dead, but will come up again in spring.

Much too late in the season for wilt to be a concern. An overly dense, excessively moisture retentive potting soil is most likely to blame but I would also give equal weight to the time of year - deciduous clematis are going into dormancy now and that appearance is pretty typical, especially for a new, quite young plant.