そいぶしにはらみし花のかきつばた
みな紫のゆかり美し
Probably the poem is related to the Tale of Genji or Ariwarano Narihira.
Kakitsubata, Japanese iris, is a beautiful flower which is often associated with beautiful women. And the word, Murasaki, or purple in the poem must be in relation to Lady Murasaki.
But what I don't understand is that the scene seems a sort of battle.