Rooms need contrast. It’s not that they can’t be monochromatic. Even within a color there can be differences in texture, pattern and shape. The greater the contrast the more striking the room is visually.
Daylily leaf streak is caused by the fungus Aureobasidium microstictum. Symptoms start with yellow or reddish streaks on the leaves, usually starting at the tip and then work downward. Eventually, the infected leaves wither and die completely.