Lines 1 and 2: I was thinking of those who fell in battle and of poppy petals that have fallen. Poppies have a lack of fragrance but death does have an odour.
Lines 3 and 4: Poppies grew on the devastated battlefields of WWI. The fields that were red with blood then are still red because of the poppies.
Lines 7 and 8: At some weddings people use natural petal confetti which is made from freeze-dried flower petals and is completely biodegradeable.