This stem got broken in a storm, so I stuck it in the ground next to a piece of cardboard tube (Sunsetter awning, comes in great cardboard tubes) where I dump organic matter to compost. It has taken root & is starting to bloom. It looked dehydrated & suicidal for the first couple weeks, but surprisingly, only lost a couple leaves before it started to look perky again.
B. coccinea, this stem was/is 3 feet tall, counting the 5-6 inches that were submerged.