A little clarification, if you please.

A little clarification, if you please.

When Mom and I shop by catalog or Internet for garden plants, we usually combine our orders to save on shipping. And it never fails. We'll find something that we both like and we'll both wind up getting it. Just recently we placed an order with Spring Hill Nursery for this bit of lovely along with some other plants for each of us. The planting directions on this lovely lilac has resurrected an old debate between my mom and me that I'm hoping someone here can settle for us. The light requirements listed for this plant are "Partial Shade/Full Sun". My belief: Plants with full sun/partial shade light requirements may be planted where they get a little shade, but you may also plant them in a location where they get sun all day long. So long as the plant does not get shade most of the day (and other basic necessities are met), the plant should thrive. Mom's belief: Plants with full sun/partial shade light requirements must have a bit of shade at some point in the day in order to thrive. Now, I understand that we're only speaking in general terms. Local climate makes a difference. A plant that can take full sun in zone 5 may need a bit of shade in zone 7 or 8. So, generally speaking, which of us is correct?
My garden..

My garden..

Succulent ID

Succulent ID

Columbine Flower Seeds

Columbine Flower Seeds

Bees and Sedum

Bees and Sedum

My Messy Room

My Messy Room

Corners of My Room.

Corners of My Room.