I don't know the ID of this begonia but it is similar to one that I have. I find this type of stem, I call it hairy, roots pretty easy in soil. Just keep it a little damp, not wet. Hope this helps. Nancy retsec

Three minutes is 1/20th of an hour, so watering for three minutes with a 50gph hose will give you 1/20th of those 50 gallons ... that's only 2.5 gallons all over the bed. Get a moisture meter, test the soil in several spots in the bed. If it's not moist, do several short waterings over a period of a couple of days until you are getting moist readings a foot down into the dirt. And MULCH over the top of everything to hold in the moisture. Then keep checking, and when it's starting to dry out 3-4 inches deep, water again. Keep notes so you know what you have been doing.

I have learned more in the interim, like the fact that even in a warm climate, it will go dormant over winter (it does that based on the hours of sunlight per day), and then will rot if it is always wet, so I plan to grow it in a pot, and move the pot into a dark corner of our basement for the winter. I had to dig it up yesterday, as it was being eaten by snails. The only stem showing was eaten almost all the way through, but there were leaves and flower buds below the damaged place, so I cut it off and dug it up. Sure enough, there were 2 other stems which stopped (as in chomped off) just at the soil level. So I think I got it just in time. It did have a round tuber. Right now it is in a 1 gal pot on my glassed in porch under an upside down small fish tank which I use for rooting roses. Gets lots of light, but no direct sun. If it survives, I will pot it up into a larger pot. The internet says they need "sharp" drainage, and I found a bag of african violet potting soil I already owned, which has lots of peat moss and perlite in it, so I used that. If it survives and grows into a decent looking plant, I certainly will post more pictures on here. I have thought of another theory as to how it got where it was growing - that was right underneath the place where my ancient, huge Anna Olivier grew for decades. It died (I have 2 bushes growing from rooted cuttings of the old one), and we dug it up. Maybe that area used to have begonias planted in it, and it came from a dormant seed of one of those. That area has definitely been gardened for the past 113 years. I have noticed that when any area in our yard which has been left alone for 50+ years gets dug up, mysterious old garden flowers pop up. It is so fun! Jackie

Maybe oedema.