Dunbartonshire,
United Kingdom 
my cortaderia sellonan has got any feather plumage why
11 Sep, 2014
Dunbartonshire,
United Kingdom
my cortaderia sellonan has got any feather plumage why
11 Sep, 2014
I have a feeling that this is a male/female plant and that the plumes are on one but not the other.
Have you had plumes in previous years - if so it may be that the crown has been damaged sometime this year, which could be all manner of causes, such as a late frost, too much water, too little sunshine.
28 Sep, 2014