I read here it's to be done in the spring. But what if it so big it is almost out of control? When the winds are high it lays in its side and on my other flowers. Right now I have propped up by garden fence.
Trimming Red Fountain Grass
Certified GKH Gardening Expert
You can probably get away with cutting back your fountain grass now. After cutting it back, check whether new, green growth appears. If so, you can use one of these strategies to protect it against any winter cold temperatures that may damage it: