With all Gobenias, it’s best to handle them as little as possible. Doing a bleach dip or anything like that is strongly cautioned against and would likely kill them. It is also best not to mist or water them until they are well established, as standing water on their leaves is enough to cause them to melt overnight. In my experience, it’s best to put them in a closed bin with pre-moistened sphagnum, lie the stem delicately down, and forget about them for a few months. They do not like to be moved, so try to resist prodding them. It is also probably best not to so much as look their direction, and maybe even think about them, as in the past this has been enough to kill them.
If they come to you potted, in my experience it’s best to keep them potted to avoid damaging or disrupting their root structure. You can put the pot in a bed of sphagnum and let the plant grow down on to that. If you receive an un-potted plant, it’s best not to bury their roots, but just set the stem lightly over some sphagnum. These are atypical Begonias in that they grow very poorly from leaf cuttings. It is possible, and I have had one success with placing a leaf upside down on some sphagnum but expect most if not all to melt with this mode of propagation. You need a good stem with roots if you hope to have a good chance of establishing the plant.
A note on temperature- while in nature many Gobenias grow along roads where it seems likely they are exposed to higher temperatures and sunlight than would occur in nearby forest, in terrariums they do not seem tolerant of temperatures above 80F for extended periods of time. In greenhouses where ventilation is better they might be more tolerant. I used to grow my plants in a basement that rarely got over 75 in the summer and the Gobenias did wonderfully, but when I moved, they sat in a hot box for a week and most of them died. I do not think temperatures were much above 85 during this period but it was enough to cause irreparable damage.
Strangely enough, even though this section of Begonias can be challenging, they also can be incredibly resilient. It is not uncommon for leaves to melt in transit, but so long as the stem is solid, new leaves will grow if conditions are good. I have had imported plants come in with just a long half rotted stem, only to rebound months later. Although many Gobenias can tolerate high light once acclimated, if you have received your plant from an importer, they seem to benefit from having shade until their root structures can recuperate. Most of my plants are grown 16″ from a LED light with a piece of printer paper taped onto the clear lid to give them some cover. This is one of those plants that you want to avoid throwing out, even if it looks dead, as it might surprise you.
Some sage advice from Stephanie Willis,
Thinking about mine, I notice they root easily from the leaf axils and less from the base of the cutting, so just placing them on the surface of sphagnum like you described is just what mine seem to respond to. They also love closed terrariums and can overrun a small one in a short period of time! I just toss cuttings in multiple environments and some will find a place that they thrive. ”
and Steve Waldron,
“They seem to do best for me when treated like an orchid (airy and nighttime drop of 10 degrees F)”
*Gobenias are also referred to Goo-benias, for their tendency to spontaneously melt into a pile of goo.