The National Begonia Society


August Part 2 – A summary of the preceding months.

February saw the start of the growing season for me when all tubers were planted and introduced to bottom heat. This was no different to any other year as far as starting up was concerned other than the fact that I had decided the previous year to have a “dabble” with pot plants during 2019. For those who know me well it would have come as no surprise that I would put my own slant on proceedings and possibly do something “outside of the box”.

All of my tubers were started in pots (cuttings in 1 litre and adults in 1.5 litre) and it was my intention to grow all of the pot plants “forward facing/180 degrees” made up of single, double and triple tubers, with the triple tubers being of two different cultivars.  My reasoning behind restricting the number of tubers to a maximum of three per pot was simply that I felt that any greater number would only lead to problems later in the growing season such as the stretching of the basal stems, stem rot, botrytis and so on. Again, for the same reasons and when using cutting tubers only one basal stem would be selected from each tuber to be grown on. I was hoping to use a number of the adult tubers as three stem plants but it soon became obvious that very few would fit the bill.  Indeed, I only managed to select two for this purpose and used another one for a double stem pot. For some unknown reason all of my tubers failed to produce the volume of basal stems that I would normally have expected and this played a great part in reducing the availability of plants grown from adult tubers.

The next stage was to pick a number of plants produced from my cutting tubers. These were selected by size and in pairs or trios trying to obtain “twins or triplets” so to speak. This was a simple task as the vast majority of my cutting tubers tend to start at the same time. In order to maintain a level playing field I also ensured that the chosen stems were at the same stage of their development as those on the adult plants.

Second pot. All selected plants were then potted directly into 7.5 litre pots (the biggest pot that I had) and moved from a peat based compost into my own soil based compost.  The reason for using this size of pot was simple, you cannon fit two or more 1 litre pots into anything smaller. Up until this stage the cutting tubers were ahead in the “easiest to select” category, however, due to the size of pot now being used the adult tubers levelled things up by winning the easiest to grow” category as initially they were the easier to manage in the larger pot. From there on in there was no significant difference in the management of the pot plants other than the pots with three stems two different cultivars.  The pots containing a single adult tuber, those containing two cutting tubers and those containing three cutting tubers (same cultivar) all grew at the same rate and in the same manner. The two pots containing three cutting tubers (two cultivars) were a different story. I knew from the start that to obtain the end result that I wanted meant that I had to control the manner of growth of the front plant in each pot. Without doing so, these pots in my opinion for various reasons would not have been worthy of growing. These two pots were now ahead in the “degree of difficulty” category, in fact one did not make the grade and was at a later stage discarded. The remaining pot stayed in front and ultimately, I only managed to obtain two thirds of the plant that I had aimed for. As viewed from the front I was pleased with the left-hand side, the top and the centre of the pot. The right-hand side was a different matter as the “plant” occupying that area had twisted during the season and ended up displaying its blooms more to the top and side as opposed to the top and front (entirely my fault and lessons learnt).  Also, because there were less buds selected on that “plant” they grew into slightly larger blooms.

In conclusion, and in my opinion, there is no difference in the degree of cultural proficiency required to grow a pot plant from one tuber than there is from two or more tubers of the same cultivar. The only difference in using more than one tuber is that you are able to ensure that the stems are positioned correctly within the pot and facing in the required direction.  In addition, and more importantly you can produce a viable tuber (cutting tuber) in year one rather than having to wait several years before it is of a suitable size to produce a show quality plant. The obvious drawback when producing a pot plant “forward facing/180 degrees) from a single tuber be it adult or cutting is that a far greater number of tubers must be started in order to achieve plants with the required number and placement of the stems.  

Without doubt the pot plant requiring the greatest degree of skill was the one containing three tubers/two cultivars provided that the grower wished to obtain the type of effect that I was after. As for the positioning of the blooms from the top of the pot to the top of the plant then that was achieved by using three stems (see photograph of pot plants  -  back row second and fourth from the left) but I would anticipate that it could also be achieved when growing two stems by obtaining side shoots on side shoots thus ensuring that more bud is formed at the lower levels of the plant.  This method of displaying the blooms is slightly different to the majority of pots being shown today and I would appreciate any constructive feedback.

For those of you among us who do not show then hopefully this diary has provided you with an insight into my approach to pot plant growing. 

Lastly, I would like to thank Brian Simmons for all his help and assistance during the production of this diary and for all of the work that he puts in behind the scene in keeping the NBS out there as having one of the best horticultural web sites available.

I will end my diary with three photographs. The first one features a new cultivar to me which I was given last year for propagation purposes. I have to admit that it looks “mighty fine” and has produced a nice bloom both in colour and form. The two remaining photographs show the proceeds of my experiment in pot plant growing shown as a multi pot exhibit within my greenhouse.  To give you an idea of scale the pots used are 12 litre pots.

I have enjoyed growing these pots and it is my intention to grow more in the future. The number of tubers allowed in a pot is now under discussion by the NBS and I have no doubt that the outcome will be published in due course.

Ian Donaldson




This concludes Ian's excellent and thought provoking series, we are very grateful to him for sharing with us his
experiences, especially the adventures into pot growing.

Cultural Diaries and previous articles