Report Designer- Bar Graph Labels - Remove Border

Using the report designer, is there any way to remove the border on the captions for the bars in a bar graph. See attached image for details, I am talking about the black box round the dates in this instance.

Also, a bonus question. Is there any way to put a label up the left hand side, saying, for example, “m3”.
I know I can have each number followed by “m3”, but that’s not really what I want. Ideally I’d like the label to be oriented vertically.