When I saw your mom's garden, and I saw your avatar of the little one, I had to post. When my kids were little, they sort of were careful of Mom's flowers, because I included them in 'gardening.' Part of that was planting things they could relate to.
I remember planting Iris Pallida. It had varegated leaves, and a distintive perfume that smelled exactly like grape Koolaid!
It's a very old iris, it's proabably for sale somewhere, I bet some of her friends might even have one to share. Come to think of it, maybe she already has one!