There are a solutions regarding using the object model floating around the web, but one easy way I figured was to actually draw a vertically-hatched pattern in a painting program and then use IT as the “picture fill.”

Directions?

1.) Save the four (they are four separate) pictures below (or, more easily, the zip file) to your hard drive. Unzip/save somewhere you’ll remember.
2.) In Excel, create your chart; then right click on the bar/area you want filled with the hatching and click “format data point.”
3.) Click on “Fill,” then “Picture or texture fill,” then “Insert from… File.” Navigate to your file. Click on it.
4.) Voila, simple, easy, hatching.