too much nutrition brown ........flush it out ...........wait i guess . i'd love to know what happens

If its been out all winter, it may be that the harshness of this last winter has killed it - remove all dead top growth back to anything that looks green. If there isn't any green anywhere, cut it down anyway, wait a while if you want to see if new growth comes from the ground, but otherwise, replace it.

Mine did the same and I cut it back really hard removing all the dead and now I have lovely new shoots about four inches long sprouting well. They are pretty tough !