Personally I would have them in separate containers. Yes, a base fertilizer is needed unless there is already some in the container compost you are using. Bone meal or hoof and horn is fine - mainly phosphatic and will be available to the plants over a prolonged period. Otherwise a general slow release fertilizer.
Use an open and organic compost for shrubs and be sure your container drainage is good.

Here is a link that might be useful: my website

I would agree about separate containers. I just know how my Prince Charles has been in its 21". LOL I've been using some bulb fertilizer on mine and that is slow release plus has a similar formulation as bone meal with some added stuff (which I use on my peony). I fertilize in late winter/early spring after I cut the vines back to the first couple pairs of buds (mine is pruning group 3).

BTW, unless the obelisk is really tall (like 5ft - 6ft), they'll blow past it. And even with the taller things, you still have to train the vines to go somewhere or they'll fall over in a tangled mess - even if trained on a rose. I put mine on a tomato cage which was about 3ft tall but where I could wrap the vines around and around the structure of it. This is what it looked like before it started blooming:

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When it burst into bloom at the end of June (really early for it), it looked like this, where it could flower near the top where it could get sun past all the shrubs across from it:

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Thanks Jenny, for explanations and pics. Um, 21" container? And I bought 3 of them??? Don't think I own a container bigger than 16". What was I thinking???? I do tend to get carried away with all these online catalogs right at my fingertips.

My next-door neighbor (who is the building manager) never even opens his patio door. Sure wish I could garden over there, too. :~)

I'm growing a climbing rose in a 20" container this season. There would be no room whatsoever for a clematis too, though I wanted to plant one in with the rose. I do have three clematises planted in three 16" containers, and so far so good. This is the 2nd year for two of them, and the first year for my Westerplatte.

Here's the Social Climber:

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I can't imagine that container could support two plants with substantial root systems.

Meg - I think the 16" will be okay - one for each! A clematis is one of those things that would be a nuisance to try to pot up gradually (which we container gardeners often do with plants). I told mine - this is your permanent home, live in it! LOL

posiegirl - I like your rose container combination and like that trellis too!

Just today I plantd a smaller cematis in with my big one and can already tell it will not work out. I didnt know they get such a huge root system.I found a sack of bone meal in the shop,no instructions. can someone tell me how to use it and on my clematis? Also, what other patio plants is it good for? By the way all the above cematis are beautiful. Mines not near as nice,got to do smething. FLOW.

Flow, here's my small jackmanii clematis. It was a stick last year! It bloomed its little heart out this year, and I'm looking for great things next year. Courage, it'll be great!

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Hi FLOW!! You just have to give yours time. Mine is 4 years old and was a little bareroot baby about 6" tall when first planted. That year it grew to about 6ft. The next year it doubled in size and after that, it was out of control. LOL

With respect to using bone meal, I just sprinkle a little around the soil in late winter/early spring. You can use that for bulbs and even peonies. Bone meal is a good source of phosphorous so really, most plants could benefit from some.

posiegirl: What's the name of the plant next to the clematis? I bought one this summer and the label on the pot said it was a variegated swedish ivy. Mine has fuzzy leaves. I'm not sure if it's accurately labeled. Thanks.

It's a plectranthus, sometimes called variegated Swedish ivy. But the Swedish ivy I know has shiny leaves. These aren't like that at all! It has proved to be a winner for me, though I have to clip it back about once a week. How about yours?