I watched a programme years ago where the chap was an expert on growing clematis. He explained that rather than shade at their feet, clematis really need moisture there. Gardeners used to put slate or something around the root to keep the feet damp and conserve moisture. He was not sure where the idea started that they need shade at their feet. I think you may find that there was not enough moisture for your clematis to survive in the warm weather we have been having. Try watering it. It might send up new shoots from an apparently dead plant.

I agree with Scotsgran - Clematis Montana love well watered soil. I was going to grow mine in a pot till I was advised that it will dry out too quickly in it and to put it in the ground (heavy clay!). The Clematis seems to love it.

Also no matter how large the pot the day lilies will have been competing for what little moisture there was... If you can't plant in the ground at least don't plant anything else with.

I've had the same sort of thing, my montana struggled for a couple of years until I discovered how thirsty they are. Mine now gets a couple of gallons each week, especially now, and I have been amazed at the way it has romped away and has flowered for the first time. It's growing up a tree and I'm seeing 3" or more on each stem every day, so before long I'll need a step ladder to carry on tying it to the trunk. Even more reason for watering it copiously as it is competing with the tree roots.

Aha. Ok, the day lillies can be moved to a bed. I only really put them there in the misguided belief that they would provide the (un)needed shade.

Unfortunately, there's tarmac by the garage so no chance of planting it in the ground but I'll get a new one and put it in the pot alone, along with some slate. It's a lovely big blue glazed pot so some blue slate would look lovely on top. I shall also tell Mum how important it is to keep it well watered.

Bernard. Your montana sounds like the one I have at the front of my house (there's a picture on here). It goes great guns even though it's in rubbish soil and never gets watered. It is shady at the root though and covered with slate so I guess I just hit lucky with that one :)

dioritt, unfortunately, C. montana is a large plant that wants to get at least 30 feet by 10 feet wide - in a pot, it can't do that, so its life span in a pot will be significantly shorter than in the ground, for it will always outgrow it within 2 or 3 years. You could try pruning it right down after it flowers every year to keep it longer in a pot, but a smaller variety of Clematis would be best.

I agree with Bamboo. Either leave the day lilies where they are and plant a new montana elsewhere or plant a summer flowering less vigourous variety in the pot. If you can cut a planting hole in your tarmac which should not be very thick, say a foot square I think you will get away with planting another montana beside your pot. Just make sure you water it.