Plants to hide gas vents
Thanks for writing. Ornamental grasses may be your best bet; they won't be damaged by the air coming out of the vents during the winter. Depending on how partially shaded it is, you might be able to get away with switchgrass (Panicum), feather reedgrass (Calamagrostis), or moor grass (Molinia).
---Justin, Senior Garden Editor, BHG.com