If you're selling, best to tidy up what you have and make it look manageable rather than spend money on plants that may well be discarded by new owners with other ideas. You don't say what aspect it is or what kind of soil you have but a couple of trellis panels attached to th efence would soften the look of that extension and make a great home for a climbing or rambling rose and/or clematis, honeysuckle, virginia creeper.......