Question: Labelling tickmarks in plot

I am making a 2D plot and need to mark certain irregular points on the x-axis, so I managed to put tickmarks (and gridlines) at those points, and somehow Maple even labels each tickmark, which is what I want. 

Except, there is no room along the x-axis for all the labels, so I need the labels to appear vertically at each tickmark.

Is  there any way to do this? The only instructions I can find for vertical labelling just apply to axis labels, not tickmark or gridline labels.

Thanks for any insight.

Please Wait...