Answer: Unfortunately, it would take any flower a month or two to reach that height. It might give you faster coverage if you planted shrubs, although that could be expensive to invest in since you are selling soon.
If you really prefer flowers, in a sunny spot you might try morning glories and moon flowers. Both are flowering vines that tolerate poor soil. The morning glories are not fragrant but the moon flowers smell wonderful in the evening. Both of these can be started by planting seed in the garden. You could set a trellis against the wall to support the vines, and that would help conceal the concrete right away as well.
In a partial shady area you might try nicotiana, it is fragrant and some varieties grow quite tall. I hope this gives you some ideas.
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