Good advice

Guernsey Donkey2

Approx. 2 - 3 years ago I grew a plug clematis Montana Rubens and at the appropriate time we bought a trellis and what we thought was a decorative pot large enough for the clematis to grow and flourish in against a south facing wall.  Well it did grow and flourish and produced half a dozen flowers in it's first full year and this year we have a couple of dozen flowers at least.  Some of you suggested that the pot we had bought was too small, however regardless of this sound advice we planted and of course you were right!  Instead of having flowers the size of saucers which is what I had been told to expect we have flowers the size of 10p pieces!  Lesson to be learned is this - if you ask for advice - take it!  You will see the flowering plant and the new pot in the pictures.  We are planning on cutting the clem down after flowering and repotting - say about Sept/Oct.

hogweed

But it is truly amazing that you have got so much top growth from that one small pot!!

Liriodendron

GD, I'd have thought that unless your saucers are very small, that flower size for Clematis montana Rubens is a bit optimistic... 7.5cm is what the books say.  But a happy plant will be covered with them, so the size of the individual flower doesn't matter very much.  

Fairygirl

I'd agree with Liri - the flowers on montanas are a couple of inches, or whatever that is in new money.
Nice pot, but I think it'll still struggle to fulfill it's real potential. Is there no chance you can get it in the ground GD?

Guernsey Donkey2

Not in this position against this wall Fairy - unless we take up some of the paving slabs which we don't want to do - they are bedded well in here. I do have another Montana in soil in a different part of the garden and it is growing well too, and you are right Liri that the flowers are not saucer size - much smaller, however I am hoping that next year there will be more of them once the plant has been repotted.  I just keep pinching out the ends of the growth - to encourage a bigger root system - water it every couple of days and feed every 7 - 10 days.  Perhaps if I didn't pinch then there would be more flowers on the plant. I believe that they only flower once a year - so I could prune and move it in Sept/October when the weather has cooled down - is that the right time?

Guernsey Donkey2

I have just found this photo taken last year - it did look so much better without all the dead twiggy bits although I don't think we had so many flowers as we have this year. Not bad for a plug plant that I only planted out at the end of the summer in 2016. It can't be all bad living in a pot!

autumnglory

I've never seen a Montana with flowers the size of saucers, I don't think the source is very accurate!

I'd say the pot is just limiting the amount of flowers you're getting; ours is the same age in the ground and when it flowers it's smothered in them. 

Obelixx

Montanas are pruned not at all or else just to tidy it up and that immediately after flowering so any severe or restorative pruning needs doing then too so it can grow all the new stems that produce next year's flowers.  You'd only need to remove about 2' x 2' of slab and then do some serious soil improvement so it can establish well and then spread its roots.  Feeding and watering till established and in dry spells as the wall and paving will limit water availability.

Lizzie27

Montanas can be monster plants, 20 ft in each direction is not unusual so I'm not surprised yours is struggling in such a small pot. I would do as Obelixx suggests and plant it in the ground, or else buy a smaller clematis.

Purplerain

I think you should find somewhere else for it. It loves being in the ground and is a most obliging clematis in late Spring/early Summer if it gets its roots down.

My experience of Montana is that I love it for early flowering, but pay it little attention after that apart from a good cut back. I would never grow it in a pot for very long.

Marlorena

I think you've done well to keep it growing in that small pot, but if you put it in the ground you will get something like this below... So much nicer I think, for the sake of just one paving slab...