Not sure what to do with your ornamental grasses?
How do you know which ones to cut back and which ones to leave?
Look no further!
There is a simple rule of thumb;
If they are evergreen leave them alone e.g. Acorus, most Carex and Anemathele.
If they turn a biscuity straw colour then they need to be cut down hard to the ground, idealy before the end of February; quite often grasses start into growth as early as February, so leave it any later and it becomes difficult to cut the old without damaging the new growth. This group would include Calamagrostis, Miscanthus, Pennisetum, Molinia, Panicum and Hakonachloa
The exceptions to the rule are Stipa gigantia which is evergreen but looks much tidier if it IS cut back and Stipa tennuissima which looks like straw but is weakened by being cut back and should, instead, be combed through lightly with ones fingers or a rake.
Lesson over, easy peasy when you know how :)