A Northumberland Alpine Gardener's Diary
This entry: 12 March 2009 by John Richards
Northumberland Diary. Entry 107.
Conservation of Plants in Cultivation
Down to London on Tuesday to participate in a Symposium to discuss future policy of the RHS in Science and horticulture. I found this a very well-organised meeting, unavoidably constrained as to time and topic, but in which many people were able to make useful contributions. Interestingly, the topics presented for discussion included none of the 'traditional' areas in which the RHS has made such a contribution to gardening over the last century. Nothing on plant nutrition, propagation, composts, pests and diseases and pesticides/fungicides, taxonomy, cultivar listing and registration. It is sincerely to be hoped that the Society will continue to invest as much time and resource on these core subjects as ever. Any new initiatives should be regarded as add-ons, not replacements.
With 350,000 or so members the RHS is a large and powerful organisation with a great deal of influence. It is not science as such, but the sentiment was frequently expressed that the RHS should be more involved with professional lobbying, particularly at Parliament, to make our strongly-held views more widely known. The Society represents a constituency almost as great as that of the RSPB, but the latter organisation is much more active, and effective, in its political pressuring.
Some of the issues many felt the Society should promote included the great reduction that has occurred in newly introduced material after the widespread practice of Rio Convention-inspired controls on the international exchange of plant material; the 'dumbing down' of specialist growers due to garden centres causing a reduction in specialist nurseries and societies; and the concomitant low number of growers, scientists and botanists that are emerging in the next generation (or amongst anyone under 45!), so that the fear was expressed that many branches of horticulture might have almost disappeared in 30 years time. This will not only impact on our environment, food production and lesure-time activity, but will have serious implications for plant conservation.
About 30% of all plant species are grown in cultivation, and the potential for gardening to provide 'reservoirs' of threatened plant species against the exigencies of extinction is incalculable and vastly important. We should all, as gardeners, recognise our important role as conservationists. This means growing, saving and distributing carefully named material as much as is within our powers.
Nevertheless, the danger is that many plant collections will also act as reservoirs of disease; the 'hospital ward' syndrome about which I have written before. I had thought I would meet a great deal of opposition, particularly from 'Plant Heritage' (the new name for NCCPG if you have not been keeping up) when expressing these views, but in fact most people seem very sympathetic to this opinion. Perhaps the swathe that 'Sudden Oak Death' is cutting through collections of rhododendrons and other shrubs, particularly in the south-west, is influencing this view.
It is generally recognised that the best policy is to save, distribute and grow carefully named seed. Cultivars are not only clones, but also seed 'strains' (such a useful word; why has the RHS banned it?) that maintain a particular group of desirable characteristics. This can lead to inbreeding (as in dogs!, we don't want Chelsea to promote Crufts-style bans on inbred lines of plants!), but the maintenance of genetic diversity in cultivation is important, and much more important than the preservation of outdated, often sick, clones. 'Cultivars are good, clones are bad'!.
To this end, seed-lists are obviously vital, as are seed-banks, and perhaps more of the seed carefully garnered by specialist amateur growers such as ourselves should be making its way into permanent storage in seed banks (this would need overseeing and refereeing, but the difficulties are not insuperable, and the benefits to future genereations incalculable). One thing we should all take note of is not only the correct naming, but also the correct storage of the seed we send to the lists of national Societies. Put it in the fridge!!
One more idea. Stephen Jury promoted the idea that the RHS should perhaps provide a list of garden plants that are of particular conservation value, usually because they are rare and threatened in the wild. Thus, a plant could be given a 'Conservation Award', just as it is given an AGM or whatever. He noted that he grew individuals of Abies nebrodensis, of which only a handful of examples persist in the wild. I thought this was an excellent way of making growers realise how important many of their charges are in plant conservation.
I think thats quite enough soap-boxing for the time being!
From time to time I mention that I have no 'wild' tufa in the garden, as I consider that its removal from the wild is as hard to justify as is the use of water-worn limestone in the garden. However, I do make artificial tufa, using combinations of moss, cement and perlite. Some of this is used within one of the alpine houses, and I thought I would feature a few of the subjects flowering in the tufa at present. All these plants have been in position for at least three years, and were introduced as very small plants into tiny holes. Since then they have rooted deep into the tufa. They receive no feeding and no overhead watering, but the tufa itself is watered in spring and summer. Here are Dionysia aretioides 'Bevere', D. tapetodes 'Brimstone', and two varieties of Primula allionii.
The other primula in the photo above is P. boveana, a good example of a species almost extinct in the wild.
Staying with Primula allionii for a moment, here is 'Beryl', in a pot this time.
'Beryl' is the picture of health, unlike 'Val' which I fear has virus. Look at the streaking on the petals. Will I have the courage to burn it?
It is curious how many varieties seem to catch virus more easily than I catch a cold, but others persist for many decades, apparently untouched. One such is dear old 'Clarence Elliott', such a favourite with so many of us, and still vigorous. Here it has just opened; the colour is true, but it darkens after a few days. Note the cutting in the plunge at the top. If a bit breaks or rots off, most root if they are put in the plunge.
Finally, two more primula pictures, this time showing how I grow petiolarid primulas. The first shows a permanent planting with Swedish peat blocks, now established for nearly three years. I have now removed the covers for the summer. The pink is mostly P. moupinensis, the blue P. 'Arduaine', the violet P.' Tantallon', and there are also some P. gracilipes, P. irregularis and others. To prolong the show life of the early varieties, some are lifted early, and others left in the ground for as long as possible.
Show plants live on the floor of an alpine house, out of the sun, until the corollas start to drop off. At this point their useful life for the season is over and they go back into fresh compost. This is important as they are heavy feeders and most of the new root growth takes place now, just after flowering. In this case, three large show pans have been put back into a new fishbox. Hopefully they will make show plants again next year. Other individuals of these clones are still show-worthy.