If you can put up what amounts to a wall of containers, you can make a fence. With the parameters you are describing, I would use a Missouri Gravel Bed or Gritty Mix container medium since both are really heavy. Then I would stick posts in some of the pots (ideally 15gal depending on the size of dog) and run some garden fencing across the posts. Plant the containers with some large ornamental grass and it will cover the fencing in short order. The grass goes dormant in the winter but it still lends structural interest. You would probably want to cut the grass back in the spring when new growth starts, but it would reveal the fencing for only a short period of time.

Good luck with this. I feel more pessimistic about it-- to get the spaces between plants to be small enough to keep a dog contained, (since it could jump on or over the top edge of the pot itself) you might risk the containers being topple-able-- not to mention a dog may feel very interested in freshly-dug dirt in containers and just dig out the plants! A less troublesome/expensive option might be to put the dog on a long rope or chain.

Invisible fence would be easier to contain the dog.

If not an invisible fence, you could add an electric fence within the perimeter of the container "fence." That would help protect the containers and discourage the dog from digging or escaping between gaps.

I'm not really a fan of chaining a dog but one thing I see once in a while is a sort of rope dog run. It's like a long, sturdier, higher clothes line that you attach a leash to. That way the dog can run around in a bigger area. The leash should be long enough to give some slack when the dog lays down, but not so long that it gets tangled underfoot. A retractable leash might work well.

For planting ideas... I'm thinking jasmine, gardenias, Knock Out or other hardy roses, any of the common landscaping shrubs in your area. I second using a tough planting medium for perennials. You could also do seasonal flowers, mums, geraniums, etc., if the pots are tall and your dog isn't too big.

my wife had a husky when she was a kid hang itself on one of those rope runs. I would never use one.

Eek! That's horrible. Yeah, don't do that idea!
First I've heard of that happening but I can see how it would. Maybe it has to do with the energy of the dog, but even then... not worth the risk.

Carol,
Walk the dog.

Forget ropes and chains, cruel. I think your idea of containers is great, could you maybe put up "decorative lattice" to block areas between planters, of course this isn't a fence, it's to provide background for the annuals, etc., in front of it.

Carol, knowing what breed of dog you have might help elicit the most appropriate suggestions. I don't believe you said you didn't walk your dog. It's perfectly normal for people to want to have their dog outside with them without being able to run away into danger, and to be able to 'use the facilities' without a person having to go outside with them.

Barrels do not taper toward the bottom, so would provide solid fence sections with no gap at the bottom like the shape of a traditional flower pot. There are individual pots that do not taper, and rectangular planters that could be purchased, or you might enjoy making some, IDK.

I would probably use evergreen shrubs, like Gardenia, Osmanthus, Azalea, Rosemary, with other plants tucked between. Knowing how much light this area should get, and what time of day, and your garden zone, would help with more specific suggestions. You can find your zone by typing your ZIP code in the box on this page. Stored in your profile (link to edit here) it will show up next to your name automatically when you post.

I don't see the problem with this.  You can also buy farm fencing wire mesh and attach it to each container to secure any gaps.  I did something similar to keep my dog from digging in my vegetable garden.