Just to update on my stevia, in case my experiences can be of any use to any one else.
My stevia plants have finished flowering. I took the flowers and hung them in a paper bag to dry; we'll see if the seed is any good or not next year.
I tried to root cuttings from the plants (I tried cuttings from both before and after they flowered), but it's been a dismal failure ~ none of them have grown roots, not even a sign of it.
As my plants are in a pot rather the ground I am going to bring them in for winter. They are very tall and 'leggy', so I cut one down to about 4 inches from the dirt to see what it would do ~ and it's putting out new shoots from the original stem! (The plant grows with those little 'section' things to the main stem, kind of like roses do, and the new growth is sprouting where the 'sections' meet, again like on my roses.)
Have to wait and see what they do over winter. I can't decide whether they'll need time in a cool, dark place to go dormant before letting them grow again or not... I may try it with one of them. Experimentation is sometimes the only way, right?