Did you take a cutting from Your Coleus?
The reason I ask is because I took a few from my Coleus
and also my Sweet Potato Vine
and put them in water and sat them in the window sill,
I have been changing the water daily since I did it
And they are growing roots! And getting new leaves too!
I have never had luck getting a cutting to root before
but both plants were VERY easy to sprout.
You should try it
Your plant was gorgeous this year
How neat to keep it growing for next year
Susie