Hopefully you left at least one leaf on each piece. It seems to need the leaf, requiring food, water to stimulate it to put out roots.
I don't generally use rooting hormone on cane begonias but you could try that and a tent made from a plastic bag will brobably help too. Especially if the heat is on in your house. The bag helps the plant hold it's moisture while it has no roots to be supplying it's needs.
Oh, zone 10, guess you don't need the heat on. LOL Ok, If it's outside, keep it in the shade until it is pretty well rooted and re-established
Hope this helps, BB

Thank you BB. The stem cutting was way over 1' and only one leaf at the end of the stem; now it's three pieces. Your suggestion of adding rooting hormone, I assume this is with planting the stems in soil and not try to root in water? I do have it indoors where I can keep on eye on it, but it's still in water and I did put a plastic bag over it yesterday. Thanks.

Seems like a lot of people grow cuttings in water, but I've had pretty poor success doing that--sometimes I keep them in water when something gets broken and I can't pot it right away, but that's about all. Good potting mix that drains well and still hold moisture, and a plastic bag is a good idea---I have had success on occasion with rooting stems without leaves by putting them horizontal in the mix, preferable with some long-fibered sphagnum moss, and quite shallow. Roots should come from the nodes, but it's slow and only worth doing for something special, like yours!

I should have taken time to look this up before I answered. There's a nice brief article on the ABS site with a picture of the begonia and of Ann Salisbury--past president of the ABS. Beautiful begonia! You shouldn't have any trouble rooting stem pieces horizontally as I said, and if the leaf is still in good condition you could make leaf cuttings and get lots of plants (if you want lots of plants!) But I'd get it out of the water fast! Canes would be less likely to be trouble in water, but I'd expect a rhizomatous to rot. Maybe that's a 'self-fulfilling prophesy'. I expect them to rot, so they do. Hope you do well with it!

You can water root it (different strokes for different folks) but keep it under some kind of humidity tent. Change the water if it starts looking cloudy. Once roots show, it should be safe to pot it up. You can root it without leaves as well as with leaves - it might take a little longer. I've done a lot of canes this summer with this method.

You can also put it in a good potting soil (moist but not overly wet) and use humidity to help root it faster.

I have been rooting a lot of rhizo leaves and canes with water rooting lately but they all do a lot better with some kind of humidity control (I use plastic bags on some and clear plastic domes over several cups in a tray on others). If a leaf stem shows rot, then I snip the rotted part off, and try another method such as sand or fast draining mix.

I am sad to say that she rotted and died :-( Thanks all for your advice.

I think I have been invaded by an infection from bad potting soil. Lots of mold for the past two years. I can barely get anything to root in water or pumice/sphagnum. Treating with copper soap and sulpher. Using the rooting powder.

I have the propomatic trays and perhaps I need to let them dry a little more often.

Need advice.

busterdog,

I'm not sure what kind of potting soil you are using but do get a quality soilless mix and perhaps incorporate liberal amounts of Perlite. I use 7 scoops of Miracle-Gro potting mix and 3 scoops of Perlite for most of my mixes now. It sounds like your soil is heavy and stays wet.

This is probably not the best time to propagate (summer and fall work better for me). What are you trying to root? Canes, rhizomes, rexes?

What I would start off with is a clean plastic cup, regular tap water (maybe let it sit for a day so excess chlorine evaporates) filled almost to the top, and either tin foil or plastic wrap covering the top (you might use a rubber band to hold the plastic wrap in place). Cut your cane or leaf to appropriate length. Trim all the bottom leaves from canes leaving the top two leaves (you might even have to cut large leaves in half so they don't transpire too much). If it is a rhizomatous leaf then trim big leaves to smaller circle (2 inches is a good size) and trim the leaf stem to an inch or two. Stick your cuttings through cut holes in the tin foil or plastic wrap. Cover these with a plastic baggie and seal as good as you can (zipper sealed bags work pretty good). Place under lights for 12 hours or longer a day and watch for roots. When roots appear and get to 1/2 inch or longer then transplant to small pot (9 oz. drinking cups with drainage holes work well) with soilless mix and Perlite. Cover the new transplants with plastic bags or another cup to promote rapid growth. Start weaning the new plants to normal house conditions by cutting the bag or tipping the plastic cup dome.

I have had tremendous success with this method. Some leaves are trickier using this method but overall it has worked with small, large, and rex leaves. 'Madame Queen' has been a very difficult one to root by leaf so I gave up on it until one of the rhizomes got snapped. I removed it and put it in a big terrarium (120 gallon aquarium) and now new leaves are coming out on this. This aquarium has glass hinged lids and I now have 3 shoplight bulbs on top for 15 hours a day.

For quickest and best results get an aquarium and put a bed of gravel in it. Place the cuttings that are already in cups on top of the gravel. With proper humidity, the cuttings will thrive. DO NOT MAKE THE SOIL WET - but rather damp. With water added to the gravel you shouldn't have to water the cups very much if at all. One aquarium I have is stuffed with just a few begonias and volunteer ferns. I add water to the base once every 4 weeks or so and then only in very small doses. If water condenses on the sides then you have plenty of water inside - you may have to vent for a few days to get rid of excess if the soil is wet.

One note of caution on the aquarium method. While your begonias will thrive in this environment, removing them may be detrimental. I would not move them before you have some other humid environment to move them to. If you can move them outdoors (provided you live in a humid part of the world) then they should do fine but if you move them to a dry part of the house, then they may curl up and die in a matter of a couple of weeks. I experienced this two years ago and learned a valuable lesson.