Thanks William, certainly gives me some food for thought! I think the beetles are here to stay regardless of planting the frittilary, so maybe using them as a capture plant is something to consider. I still have my Martagons that I treasure and up to now have been relatively spared ( in part I think to their situation in more shaded areas of the property), but also a few remnants of asiatics and oriental/ trumpets that have survived the 'big cull' and that I would like keep. I've never tried Crown Imperials due to hardiness issues.
