Hello!

I purchased this Asiatic Lily (not sure of the exact name) back in March. I live in zone 8a in a townhouse, which only has south-facing windows. My exterior area has no shade except for a few hours in the high afternoon. I keep the lily outside, where it seemed to be thriving until recently. Texas summers are intense with temps often reaching 100 degrees, so I typically move a few of my outdoor plants inside for the season. After noticing the yellowing on the upper leaves only, I moved the plant inside where it's doing okay. This is my first Asiatic lily, so I'm not sure if they're susceptible to sunburn or anything like that- Would anyone be able to identify what could be going on here? The plant shows no signs of root rot, and the only yellowing leaves are the ones up top here. There are no signs of pests or fungi. The affected leaves aren't wilting, just yellowing. I water wet-to-dry and fertilize with a diluted mixture once a month during the growing season. I bought the lily because I thought its foliage was beautiful too, and I'm worried I may be doing something wrong.

This is the plant's bloom, back in March.

This is the plant now, with yellowing foliage.

Any help is appreciated!

-Jesse