Two things probably happened here. One is the ageratum effect where
some blue and purple flowers just don't record on film the way they look
to the human eye. This alone usually causes a washed out look with a
lack of color in the flowers. Filters can help you get close to the
original color, but usually at the expense of different colors in the
photo. The other is that purple and blue flowers usually look best on
overcast days and usually don't look that good in the yellow light of
late afternoon sunlight as the colors oppose themselves.
Archy E. Wiseman
As the previous poster stated, light overcast days are frequently best
to reduce contrast and provide the eveness of illumination.
In addition, with the lens accessories indicated, I wonder if there was
enough intense light reflected back to cause flare problems.