I live in Southern California, and my backyard is a concrete box. Filled with a pool, and there are only grass and a planter box in one corner of the backyard. We're going to be renting and possibly selling the house in a couple of years, and I'd like to do something to make the backyard a little more appealing.

You can see my mutated panorama here:

http://i.imgur.com/zUrqn3u.jpg

The image makes things look a little skewed; the backyard is about 60 feet wide. We will be ripping out the monster Rosemary bush that is there in the planter box.

I would very much like to do something across the concrete wall in the back -- something to add some greenery and flowers, if possible. Right now, when you're in the backyard, it just feels so sterile, gray, and concrete-y. Our options as far as places to grow from are very limited, as you can see, because the pool and the walkway take up most of the backyard. We can't dig that out, so we're stuck with what we have. We're also on a fairly limited budget.

So, my questions:

- what kinds of vine plants have the longest growth/stretch? What would you recommend that we use here to cover as much of the back wall as possible?

- how much of the back wall can we realistically expect to cover with a creeping vine/plant?

- as you can see, the only real soil to grow out of is the planter box on the right. We could theoretically, place some sort of non-permanent planter in the far left corner (so long as it doesn't impede the walkway too much), but I'm not sure if that would be suitable for a creeping vine. Thoughts?

- my friend recommended attaching a trellis to the concrete (she has a similar backyard wall, and planted morning glories. She has a lot more dirt than we do, though). How involved is this?

- are there any negatives that we should be aware of when it comes to planting a creeping vine?

- how difficult is it to maintain this kind of plant? We're not really gardeners. The box on the right has sprinklers in it, so we can control how much water (and how often) goes there.

- projected cost to take on something like this?

Basically, I'm doing research now to see what our options are (if any) -- any thoughts or suggestions on how to make this backyard more green looking are greatly appreciated!