UNUSUAL EXPERIMENTS WITH TUBEROUS BEGONIAS by Ralph Willsmore
Sometime ago I set out to produce tubers of varieties I thought was becoming very scarce. But that became a disaster as I could not obtain materials I normally use for propagation. So I hope the couple of methods may increase your stocks of named varieties of Tuberous Begonias.
On the 27th April 2020 I had a young vigorous plant of ‘Becky Jane’ which I decided to take a cutting from; a mallet cutting was taken from a flowering bud section of the plant with no growth buds whatsoever. I put neat purple clonex® on the wound of the cutting, I then thought this might burn the cutting so I wiped off the Clonex off the cutting as much as I could. It was then placed in a bottle containing filtered mains water. And placed it in my little plant propagator which was set at 25ºc, it also had a tiny grow lux and fluoro lights for fourteen hours a day. This is most important as otherwise the cuttings will go dormant. To my surprise in about 4 to 5 weeks the cuttings had callused and were forming multiple growth buds. Another month on there were several shoots growing vigorously on the cuttings. The growths were small and I took several as cuttings but only 2 survived as I had my propagator too wet and humid, which made them rot off as they were extremely soft. Two survived but only one made a good tuber. The pot in the accompanied photo shows a 2 inch pot, so they were very tiny tubes.
In May 2021 I repeated the procedure with a cutting from the plant of ‘Blushing Bride’. I took the cutting from the top of the plant before it was about to die down, the top was still very fresh. It was a mallet cutting which had no growth buds, I put purple Clonex® on the cut surfaces and once again wiped it all off, and put it in water. After some time it took roots and started to form shoots. I planted it in a 4 inch pot very close to the surface, where I will only be able to retrieve 1 or 2 cuttings above ground. Some of the shoots are below soil level and will probably not develop.
‘BLUSHING BRIDE’ CUTTINGS BELOW
KEIKI GROW on Tuberous Begonias
A friend of mine, John O’Hara, told me about a product called Keiko Grow® available on the internet for about $35.00, A VERY TINY TUBE BUT IT GOES A LONG WAY. This product is used to produce adventitious buds on certain orchids. I tried a few cuttings with limited success but then I tried it on a leaf or petiole cutting of the variety ‘Uluru’, and this cutting produced two adventitious buds on the cortex of this cutting, which eventually formed two tiny tubers as in the photo.
I cut a leaf with stem fairly close to the main stem of the plant, I then cut a narrow piece from the side of the cutting to expose the cortex in the stem as this is where the adventitious shoots are more likely to appear, a small amount of Keiki paste was placed on the cut surface, the process produces a white substance on the cutting before the shoots appear. Two buds appeared while the cuttings were in water. So I then planted the cutting in the 2 inch tube. It took months for a shoot to appear from the surface of the soil, but finally one did. The leaf maintained a healthy appearance throughout. When it was finally harvested I was left with two tiny but healthy tubers, and they are showing signs of growth buds. Neat purple Clonex® would possibly produce adventitious buds if it was put on the cut surfaces and then wiped off with a tissue. Definitely do not wash off.
MORE CUTTINGS FROM TUBEROUS BEGONIAS
If you have a named variety of tuberous begonia which produces little or no side shoots for cuttings you can try the following. The plant used in this exercise was the variety of ‘Alyce’ which is shy of producing side shoots, it was growing in a 6 inch pot in late Spring early summer when the top of the plant was removed, and it was cut between the last bud growth node and the first flower bud node. The severed section was cut into sections producing three mallet cuttings. The plant was then repotted into an eight inch pot and it produced multiple shoots, some of which were used as cuttings.
MALLET CUTTINGS OF TUBEROUS BEGONIAS
In the late 1980 to early 1990 we grew Elatior (Heimalis Begonias) commercially, and one way of propagating them was by mallet cuttings. That led me to try Mallet cuttings with tuberous begonias. The first attempt using neat Clonex® on the mallet cuttings was fairly successful in late spring to early summer, but as the summer heated up the clonex tended to burn the cuttings, so I diluted the Clonex® with water. That was not so successful with the mallet cutting .
The first attempt produced many adventitious buds, sometimes a complete ring of them around the top of the cuttings. The resulting tubers from these cuttings left a lot to be desired, They resembled a cluster of haemorrhoids , so I modified the mallet cuttings by cutting away a section of the main plant stem, which produced tubers of a normal shape. I have now gone back to using complete Clonex® and wiping it all off. When wiping it of I feel some of the Clonex® might go into the surface of the cutting. This is working very well in the cooler months, but I have not tried this in the hotter months as yet.