Blue wood sedge in flower

This is my northfacing windowbox. It contains maidenhair fern, wild columbine, wood poppy, common blue violet, and blue wood sedge (Carex flaccosperma). It's bluish-green leaves overwintered (evergreen), but are tender, so they do get brown.

This plant shouldn't be in flower until the end of April, but I guess no one told it that. You can clearly see the male flowers - the lemon yellow anthers - at the top of the inflorescence. The female flowers - clear stigmas - have yet to emerge below.