Day-long exposure to full summer sun, 85°F to 95°F, will cause many daylilies to melt, brown, or wilt. Daylilies here are evaluated for sun resistance at 7 p.m. or later, and I describe the condition of the flower as follows:
Outstanding – The outstanding category is reserved for flowers whose color and form has changed very little, even at temperatures 95°F – 100°F. Few blooms can show sun resistance after 100°F, but a few can do so, and are so noted.
Excellent – Examples of the excellent category of flowers remain in relatively good condition throughout the day and into the evening with very minor changes in substance and color.
Good – The good category is for flowers that show some fading and/or a hint of discoloration. The overall garden appearance of the flower is still good into the early evening (7:00 p.m.) hours.