Ornamental grasses arent the best for hiding ugly things year round. They should be cut down to a few inches in spring, leaving a gap for a while til it grows in again. Really an evergreen shrub or large perennial would be your best bet. There arent too many grasses that can stand shade. Good luck!

Jen

Go to the bamboo forum.
Evergreen screen year round.
You can keep them in check with a lawn mower.
Many bamboo like shade and several are meant for wet conditions.
The folks at Bamboo forum will help you out.

Please one thing! if you put ornamental grass next to your propane tank, make sure it's not the kind that's really sharp bladed. Our poor LP man came over the other day and he'd really had some trouble with some bushes and ornamental grass trying to fill a tank. FYI...

Can't you camouflage it? That's what we did with ours and it's not great but it makes a 500-gallon tank a lot less visible. Only issue is it has to reflect heat... There are good tips around

Here is a link that might be useful: Tips to hide propane tank