KTRS 550 Inside Out Show Bonus Info Kiss Your Grass Goodbye

Did you Mean to Kiss Your Grass Goodbye?

by MaryAnn Fink
Conservation Specialist
copyright 2010

When to cut back ornamental grass is a source of confusion for homeowners. I receive calls frequently in mid-late spring about hardy ornamental grasses “that were fine last year but have not grown back this year”. After further questioning, I am seeing what seems to be a related pattern that involves the following sequence:

1-Yardeners: homeowners anxious to do something/ anything to be outside and get ahead of spring,
2-A situation that involves “Flat top/ fall out” grass debris after snow melt
3-Early / late winter cutting back grasses before green up occurs

This pattern can lead to kissing you grass goodbye:

1-sever die back at crown level
2-irregular crown growth
3-crown rot / total demise

Some sources tell people to cut back grasses in late winter, some say early spring. "Which is it?" My answer is species dependant: Most but not all ornamental grasses are actually warm weather grasses that don’t begin growing till spring warm up is consistent. So know your grass category. Cool season grasses can be cut back as soon as you see your cool season turf grasses such as fescus and bluegrass begins to grow.

My best guess from years of experience with this that the warm season grasses appear to be getting some protection from the growth, keeping them buffered from fluctuating temperatures, cold snaps and from getting “over wet” from spring moisture by the pervious year’s growth acting as a insulator and umbrella for the most sensitive part of any grass- the crown.

I suggest if you must cut some amount of the weathered grass early because of “flatten grass sprawl” or breakage- cut only half or the most offending part of the grass, but still leavie a good amount of the dense last year’s grass shafts to keep the tender soft crown of the grass at ground level warm and dry.

All this talk of warm and cool season grasses (and please note some are annuals in Missouri) has probably got you asking a few questions such as , "Just which ones are hardy? Which are warm season? And, which ones are cool season?" Also there is some concern that grasses trimmed a little late might lose the tips of the newest growth. My question is- would you really notice and would that ruin your season?-I hope not. I do not think most people ever examine their grass tips once the season is moving along!

Below is a chart of some common ornamental grasses. Note also that some grasses are not winter hardy in Missouri but still provide many of the same attributes without the periodic division/ care that is required at least occasionally (every 3-5 years -depending on the grass) This division need raises the care level for these plants at maturity.

Also note that fescue ( Festuca) and Helictotrichon can be evergreen in mild winters and are more likely to suffer and or die out from our heat in the summer. Also some of these grasses may not need to be cut back but might have to be re-planted just like the annual grasses, so these might be best considered a seasonal plant. If they were planted in the fall, and still look pretty good by the end of March, instead of a haircut, they might just need some grooming, more of a “comb out” of any worn foliage on the outside perimeter of the clump. I will add a list and links to Missouri Botanical Garden as I get time for now do your own reseach about your grass- before you kiss your grass goodbye!