Lilies dropping leaves like crazy?

Lilies dropping leaves like crazy?

First a little back-story... I recently started working in the floral department of a chain super-store, and I hardly know anything about flowers and such. I learn a little here and there, but my bosses aren't terribly helpful. I thought maybe if I joined a community like this I could learn from people who are actually good at caring for lawns and gardens. I appreciate learning from pros. :) Anyway, we have some potted "Oriental" lilies (sorry, tags aren't always specific) that have been dropping leaves before my eyes. I'll budge the pot a little and a leaf will fall off. The leaves are green and healthy looking. Is this... OK? The flowers themselves are opening fine, they're white with pink speckles. Not sure if watering is an issue, the soil always feels fairly moist. Thank you very much!
Ok, some random photos of my back yard… and a question for all you tree people.

Ok, some random photos of my back yard… and a question for all you tree people.

Plant Identity

Plant Identity

summmmmmerrrrrrr!!!

summmmmmerrrrrrr!!!

Bow chica bow-wow.

Bow chica bow-wow.

My crib.

My crib.

Sharing springtime flowers

Sharing springtime flowers