Hi Connie,
Tuff question!!!I called a large nursery near here because the only thing I could come up with off the top of my head was a Dawn Redwood Tree. It gets very large! And also there is a rose called 'New Dawn Rose' and Bordines does sell it.
Anyways, the people at the nursery have posted the note and will call if anyone can think of anything. Many roses have women's names but they didn't come up with anything right then. They thought there might be a mum with Connie or Constance in it.
Ever think of 'naming' a favorite plant after each sister? I heard of a grandma that would purchase a special plant for each grandchild, label it with a nice label with each of their names and the kids were always excited to come and see 'their' plants. That way she could pick a plant that maybe was a favorite color or the correct plant for the location. Just a thought.
Bye, Diane (I'll write back if the nursery comes up with anything.)