How to Be Sure My Mandevilla Plant Is Completely Dead?

Question

I can’t find any green whatsoever on 1 of my 2 potted mandevillas.  When I break a branch, there’s no trace of green. It’s a goner, right?

Answer 1

Yes, it does sound as if it's a goner. However, this article may help you determine that for certain: https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm

Answer 2

It sure sounds like it. Sorry. ...We have a highly technical method of determining if a plant is indeed deceased..."snappy, bendy"! If you grasp the stem between both hands and try to put both ends together and it snaps, it's usually dead. (and I mean you can hear the snap). If it bends (flexes) before breaking, there is usually some life left in the plant. Of course, there is always scraping the bark to the cambium cell layer to check for vitality!
This article might help: https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm