IT WAS FASCINATING to hear Andy Allan describe how he converted an old outbuilding into a hi-tech dahlia production line. At our seminar in Perth, he outlined in detail how he had created an ideal environment - with controlled lighting, watering, heating and humidity systems.
Andy is to be congratulated. Some years back I toured a similar unit but it was within a horticultural research station in Holland. Now, in Scotland, albeit on a smaller scale, a dahlia enthusiast has set up a similar science based unit - and added a new dimension to our hobby. Indeed it has prompted me into paying £19 for a mercury lamp, hopefully to kick start my usually reluctant ‘early tubers. Hardly revolutionary - but a significant step for an old fogey like me.
Needs, of course, are the parents of invention. Andy, each
year, puts out around 600 plants and obviously aims to start off
with at least double that number of cuttings. That scale of operation
demands sophisticated facilities. A unit that can guarantee not
only a mass of cuttings - but to provide them at specific times.
Other large growers, like champion David Boyd (about 800 plants),
emphasise the advantages of having selected plants to put out,
all of the desired “age”.
Andy has created a system to match his requirements. His recent
show performances provides evidence that it works. He is one of
many modem growers turning to technology. Some attracted because
of production needs, others simply by the saving in time and effort.
Nagging Doubts
This hi-tech trend, however, tends to nurture doubts among many
“traditionalists”, whose needs are apt to be a bit more
modest. They still over-winter tubers and “set ‘em up”
in the time honoured fashion, eventuaDy selecting the likeliest
off shoots. Many of the old brigade suspect that “factory
style” propagation, on a large scale and within an artificial
environment may heighten the ever present threat of disease. If
for no other reason than the material is being started off earlier
and kept growing, in situ for a longer period of time than under
traditional techniques.
Everyone has experienced the hassle when tubers fail to survive a long winter. Or prove to be ‘blind’. Or produce eyes weeks behind schedule. Commercial suppliers, not surprisingly, embrace modern technology to ensure that such difficulties do not arrive. They use systems to keep stock “ticking over” during the winter. Business depends on being geared up to meet all orders on time. Nevertheless, it is still not unusual to hear complaints about the quality of cuttings sent out each spring. Intensive propagation methods are being followed, to varying degrees, by an increasing number of serious exhibitors. It is now pertinent, perhaps, to question whether such methods really ensure the best quality of young plant?
Many of us, if pushed, might contribute doubts based on personal experiences. It is not uncommon, for instance, to spot premature budding, in the pot, among “bought in” cuttings. This phenomenon is usually attributed to a growth check. Or, as sometimes suspected, it may be the result of a nursery sending out what were actually cuttings from cuttings. Shoots taken from a “mother” cuffing, back in the nursery.
There is, however, a further field for concern. One which may be of much more significance to serious showmen. This is whether such techniques, particularly if deployed winter after winter, tend to dissipate a particular stock’s inherent strength? This aspect of the technology trend may represent a latent threat to maintaining quality within a particular valued variety. Old time growers, not just of dahlias and chrysanths, placed great emphasis on stock control. They preached the necessity to rogue stock health; to identify individual plants for bloom standard; and to employ methods aimed at maintaining “vigour”. It is generally accepted that a dahlia variety gradually loses its natural vigour, as one yearly cycle follows the next. Many of us, over the last 20 years, have personal experience of how it became difficult, for example, to maintain size within the highly popular Scots family of ‘Marcs”. Is there a danger that “forced” production techniques would have the effect of putting this natural ageing process into fast forward mode? So that vigour is dissipated even sooner?
Tampering with Mother Nature
Man knows, to his cost, the danger of tampering too much with
nature. Plants that produce a tuber anticipate a dormant season.
The dahlia’s natural cycle, I would suggest, hardly seems
consistent with a technique devised to keep a tuber (or its selected
late cuttings) ‘ticking over” (or indeed growing on)
through a winter. Then inducing early growth to produce a mass
of growth on the bench.
What value nowadays on “rested stock”? This was an old fashioned technique of the top showmen to ensure they retained tubers from carefully selected plants. These were carefully nurtured not allowed to flower, and were earmarked for future stock production. Was this practise based on a complete fallacy? Was it some old gardener’s tale? Was giving em a deliberate rest really a waste of time and compost?
Ron Hatfield, an executive member of the National Dahlia Society, has involved himself for more than 40 years in studying tubers. Three years ago, in an article, he noted that the technique of “rested stock” was a recognised method for preserving vigour and health. He pointed out that he, himself, still had good quality “Kidd’s Climax” despite that variety going back over 30 years. Then he observed, rather apologetically, that “Rested stock is a term heard less nowadays”. Indeed.