I will add this to the "Learn something new everyday category". I thought I would share. In a facebook posting, by Prairie Moon Nursery, entitled "Got Stems?", I learned that native bees lay eggs in the stems of native flowers.
Gardeners should leave their natives in place through the winter, not only for the birds but the bees as well. I always leave my messy stems up through March (sometimes later) for the birds. I would think they need to stay in place until the native bees start to emerge. I am not sure when that is in my area. This calls for more research.
Here's to a messy garden!