Most, but not all, ornamental grasses die back in the winter time. Whether it is our natural instinct to cut something back once it has died back, or just the neat appearance given by having the grasses cut back, they are best cut back in early Spring. Cutting grasses back too early can lead to damage or even death. Knowing when to cut them back is as easy as looking closely, but you have to know for what you are looking.

When it comes to cutting back ornamental grasses, everyone seems to have the same misconception; cut them back as soon as they are brown. This is not the best time and can jeopardize the health and life of the plant. If you have been in the industry as long as I have, you have seen your fair share of customer’s, or your own, grasses that have either had a significant portion of the plant not come back out in spring, or they died completely. This is normally due to cutting them back at the wrong time of the year. The dead, brown grass that remains in the Winter season acts like an insulator when the cold weather moves in. This keeps the grass’ root system from freezing out when it’s real cold. Even more importantly, this uncut grass deflects and blocks a lot of moisture from getting in the crown of the grass. When the crown of the plant stays too moist, you will get some loss. Another issue with cutting your grasses back too early is it leaves open stalks of grass exposed to rain and the elements. When moisture falls into those cut blades of grass, this promotes moisture damage and crown rot.

Here are some great tips on cutting back your grasses:

  • Do not cut ornamental grasses back until they begin to push out of the center of the plant, normally in early When you see new, green growth emerging from the center, you want to cut the grasses back before the new shoots are around 18”.
  • Use a piece of string or rope and wrap it around the clump of grass before cutting, starting about 18” from the bottom of the grass and working your way up, spiraling. Cut the grass just below the bottom of the string, leaving about 15”-18” inches of the grass.
  • Simply remove the cut grass and dispose of it. Using the above method can save you hours in cleanup time.

Author: Josh Smith