How to Propagate Begonias From Leaf Sections

So. You want to propagate a Begonia, eh? Well, here's how to get a ton of plants (and I do mean a ton) from a couple leaves.

You will need:

1 clear plastic clamshell container of cookies, donut holes, or other delicious baked goods (yes, it is critical to the success of the propagation that the baked goods be delicious. Anything with frosting is good.)
1 pair of scissors
1 Begonia you wish to propagate, or at least a couple leaves from someone else's (who you asked permission from first, of course, as you are not a thief)
1 assistant (optional)
1 small piece of stiff, flat plastic or metal (e.g. a plant tag, credit card, etc.)
dishwashing liquid
vermiculite
water

Step 1: Open the container of baked goods and eat them. If you can't finish them on your own, ask your assistant to help. A previously-emptied container can be used, of course, but it's not really in the spirit of things. Remember: this is one of the most legitimate-sounding excuses you're ever going to have to buy donuts, so you'd be a fool not to take it. ("But honey, I need the container for the Begonias I want to propagate.")

Step 2: When the baked goods have all been eaten and you feel the sugar buzz beginning to come on, wash out the inside of the container with dishwashing liquid and warm water. (This is also a good step to delegate to an assistant while you eat the last two of whatever they are.)

Step 3: Fill one side of the container about half-full of vermiculite. Add enough water to completely soak the vermiculite. Drain off any excess. You want it all to be completely wet, but you don't want any standing water, either.


Step 4: Get the leaves you want to propagate. If you're taking them off of your own plant, try to get a leaf which is old enough to be fully-developed, but not so old that it's been damaged or discolored.


Step 5: Use the scissors to cut a circle out of the leaf around the petiole. It doesn't have to be huge; an inch (2.5 cm) in diameter is plenty.


Step 6 (optional): Cut away any jagged edges from around the outside edge of the leaf. You don't necessarily have to do this, but it can make the leaf pieces a little easier to work with and a little more uniform in size, and it can also give you a few extra leaf sections later on.


Step 7: This is probably the trickiest step, which is unfortunate, since by now the sugar buzz is probably beginning to fade. Cut the leaves into sections between the main veins of each leaf, so that each section has a main vein at its center. These larger veins are where the new plant will originate. If you cut pieces off the margin of the leaf in step 6, you can cut a few wedges out of the margins as well, again with a primary vein at the center of the wedge. (In the picture below, the five-sided wedges on the right were taken from the margins of the original leaves; the more triangular wedges on the left came from the inner part of the leaves next to the petiole.)


Step 8: Use your stiff piece of plastic or metal to slice a number of evenly-spaced slices into your wet vermiculite. If the vermiculite is runny and the slices close back up after making them, drain off some more water and try again.

Step 9: Insert the leaf wedges, narrow end down, into the slices you've made in the vermiculite. You can also take the original petiole, with its circular bit of leaf, and plant it in the vermiculite as well, though I didn't. (No particular reason. It may be that I forgot that that was an option, or that the sugar buzz was long gone by this point and I was just trying to hurry through the rest of the process.)


Step 10: Put the top back on the container and set the container in a warm, bright location. Ideally you want about 80F/27C, but this still works if it's cooler than that. I don't necessarily recommend a spot that gets direct sun (too much sun can get too hot for the leaf sections), but it is not actually the end of the world if there's a little direct sun, particularly if it's filtered through a sheer curtain or other plants or something. The leaf sections in this example did get a small amount of direct sun.

Step 11: Wait. I started the leaf sections in this example in late July and saw the first new growth in late September. By mid-October, four of the 22 had sprouted leaves. None of the sections have died.


The main hazard with doing this is rot, which is why I used vermiculite instead of soil -- vermiculite is sterile, or at least really ought to be, and as long as the container is closed most of the time, the chances of a pathogen getting in are pretty minimal.

Another, worse option is to use regular potting soil, but sterilize it by pouring boiling water into it. The disadvantages with this are: you can't pour boiling water into one of these clamshells without melting the plastic, you can't stick leaf sections into hot soil until it's cooled down, and the sterilization may or may not be complete, or may be undone by something landing on the soil while it's cooling down.

Plants can be left in the clamshell for quite a while without a problem, but I would pull them out and pot them up once they get big enough to touch the lid of the container, or have three or four leaves, whichever happens first. For best results, try to ease them into regular life gradually, by propping the lid open slightly, then a little more, and so forth over a period of a few days: otherwise the change in humidity will hit them all at once and they'll suffer for it (it will probably not kill them, but they won't like it).

This method may not work on all Begonias: I've personally only tried it with the variety you see here, though it's supposed to work for all rexes, angel-wings, and other varieties with large leaves. Plants with small leaves are more easily propagated by leaf cuttings: cut off a leaf with a petiole and plant the end of the petiole into your rooting medium (sterilized soil, vermiculite, or whatever). Cane-type plants are more commonly propagated through regular old stem cuttings.

Each leaf section you plant is capable of producing more than one new individual. My experience has been that two or three is fairly typical, and actually, so long as the medium remains sterile, rumor is that one can remove the new baby plants from the leaf wedges and then put the wedges back in to root a second or even third time. In theory, then, the two leaves I started out with here could be turned into approximately 150 new plants. (It'd be okay with me if things didn't go that well, though. I don't even like Begonias particularly.)

So don't ever complain that you don't have enough Begonias to take care of. Nobody will believe it, they'll just think you're begging for free Begonias in a weird passive-aggressive way, or they'll think you're really stupid.