Let's say you're in-game looking at the floating grass, here's what to do:
* Go into the console, enter TG then enter. Now you will have the http://img838.imageshack.us/img838/1356/cellz.th.jpg of the cell where the floating vegetation is. Write the position down, or take a screenshot.
* Start TES Construction Set. Go to "File", "Data Files..." and tick Morrowind.esm and Vurt's Groundcover - BC, AI, WG, GL.esp, click "set as active file". You might also want to tick the mod that is affecting the landscape if you want to see how it alters the landscape/grass (do NOT set this as active).
* Click "World", "Go to Cell", enter the cordinates you wrote down, hit enter. This should take you to the affected cell.
* Drag and select the whole area with floating vegetation, it does not matter if you select rocks, trees or houses. Hit the Del key. If you're deleting a whole town for example you'll get a lot of annoying messages where you're supposed to click ok, just hold Enter to skip through all those messages.
* "File", "Save"
* http://mlox.googlecode.com/files/tes3cmd-0.37p-2011.05.23.7z
* extract this exe to the root of c:\ and also copy Vurt's Groundcover - BC, AI, WG, GL.esp to c:\
* copy this text (ctrl+c): tes3cmd delete --instance-no-match GRS_ "Vurt's Groundcover - BC, AI, WG, GL.esp
* Click the start button, write: command prompt in the search field, click its icon.
* enter cd.. (hit Enter) untill you reach the root of C:\ where you copied the .esp
* Right click in the window, "paste" (ctrl+v does not work), and hit enter. This procedure will undelete everything (rocks, houses etc) except the floating grass that you removed.
* You now have a compatible .esp. There's no need to ask for my permission to share this file.
Credits: Dragon32 for the tes3cmd instructions.
Questions or suggestions for improvements are welcome.