I have a tricky question!

I was hoping someone would be able to advise me on some very hardy screening plants for two small areas in my property in London.

The property is adjacent to a drycleaners. There are two small paved outdoor areas on the property that I would like to utilise. They are currently quite neglected and I would like to nicen them up with some greenery.

The problem is that the plants need to be heat and steam resistant as during the day the drycleaner expels steam onto the areas. While this wont affect my use of the areas (as it only occurs while I am at work), it does mean that the plants will have to withstand this abuse.

In one area, an exhaust access slowly releases the hot air from the drycleaners over the course of the day. In the other area, it is one blast of steam from the boiler once daily in the afternoon. The first area is a roof terrace that gets nice afternoon sun. It has a very low wall (knee high) enclosing it. The second area is enclosed on three sides by high walls. It gets very limited morning sun and is quite shady the rest of the day. In the first area I had in mind running some low potted plants following the wall. In the second, I thought of full height (again potted) screening plants, to disguise one of the walls and generally green up the area. (Although I wouldn't want anything too large to intrude on the space). With some greenery and nice lamps, it would be lovely in the evenings.

I am loathe to simply give up on greening the areas; in central London outdoor space is limited and it would be such a shame to let it go to waste. Do you think that it is possible to find plants to withstand this treatment?

Thank you for your help!
Cara