A question about asiatic lillies??
Answers:
Lilies go into a dormancy after they bloom. Most likely your cutting them tricked them into thinking they were done for the year. Also, it could be caused by dry conditions....if you have any there now. Lilies like to be moderately moist. Don't worry about it too much though...your cutting them like that actually did them a favor...by cutting the stem, the energy went from producing big , beautiful flowers to feeding the bulb...that is actually a good thing...your flowers should be even nicer next year!
Other answers:
This sounds normal. It's nothing you've done to the plant. I've got Asiatic lillies in my yard and after the blooms fade, the stems go dormant. They turn yellowish brown. It's part of the life cycle of the plant. The bulb isn't putting energy into the stem part so it starts to die back. The bulb is actually storing food and nutrients to see it through the winter.
This sounds normal. It's nothing you've done to the plant. I've got Asiatic lillies in my yard and after the blooms fade, the stems go dormant. They turn yellowish brown. It's part of the life cycle of the plant. The bulb isn't putting energy into the stem part so it starts to die back. The bulb is actually storing food and nutrients to see it through the winter.