Our patio is covered by a balcony overhead but we need some protection from the afternoon sun. We have crepe myrtles on that side of the house but deliberately didn't plant them to cover this hotspot because the sun is nice during the winter months, But in the summer it makes the space virtually unusable in the afternoons when we would like to cook out, etc.

I thought I might plant vines in planters to give some shade that could climb strings that I anchor in the planters leading to the balcony's rails.

Would this be a viable plan? If so, can someone suggest fast growing annual vines that I could take up at the end of the summer?

I can post some pics of the (very unattractive, bare) space that I'm working with if that would help.