I have been given what I believe to be a fountain grass but a lot of the grass ‘leaves’ are partially dead, at the ends. Should I extract the whole of the leaf/blade of grass or add something to the soil? Is it best kept in a pot or planted in the garden? It is also looking very untidy and bedraggled from its transport, so would it help to trim it right back and, if so, how much? Is it too late to do it this year? I have seen an article referring to fluffy caterpillar like flowers on a Pennisetum so I think this may be what I have.
I would trim your fountain grass back 4-6 inches above the ground to get rid of the dead looking ends and, no, it is not too late. More information on pruning fountain grass can be found here:
As for where to plant, it's really a matter of personal preference. You can plant your fountain grass in a container or in your garden.
For more information on fountain grasses, please visit the following links: