Kent Alpine Gardener's Diary
This entry: 13 May 2017 by Tim Ingram
Propagation - a practical meeting.
Propagation - a practical meeting.
Considering that the fundamental basis of any garden (and any plant) is propagation, we speak about the practice of doing this far less than so many other aspects of gardening with, exhibiting, travelling to see, and the botany of, alpine plants - as though in some way it is a given. In fact practical meetings, when we hold them, tend to be those with most audience participation and interest, and for many new members of the AGS are probably amongst the most valuable of all. So this is just a short description from our last Local Group meeting in East Kent, looking in particular at propagating alpines (and other plants) from cuttings. This was led by Jeremy Spon, who concentrated on the various mediums and techniques that he uses, and my wife Gillian, who looked in more detail at specific plants, timing, and care of cuttings through the process of rooting.
This picture proves the point, and it was an enjoyable evening - rather different from our sometimes very erudite explorations of alpines in wild places - and leads us to think that we should use meetings such as this more as a potential way of attracting new members. (In fact we find this difficult, like many small Local Groups, despite trying different initiatives from opening our gardens to preparing a display at the Kent Garden Show, but the very effort is stimulating and revealing, and the social media now gives the oppportunity of getting information out more widely to the local population. In Kent we have now set up a Facebook Page for the Kent Groups, with the aim to integrate information about meetings and become rather more pro-active and imaginative in sharing details of what we do - https://www.facebook.com/groups/1105898012869892/. Lots more could be said about this, and probably should be, if the Society is to capture a new audience, and I will probably return to this later with reference to the Easter Kent AGS Show, which acts as a focus for plants-people in the south-east).
Jeremy began by taking us through the advantages and disadvantages of various different rooting mediums for taking cuttings, many of which will be used successfully by many gardeners - the essential features being retention of both moisture and air. What he uses most is a purely mineral mix of durite (a very sharp 'sand', made locally by heat treatment of crushed flint) and perlite in equal parts. But he also experiments quite widely for different plants, especially when successful rooting has been poor for some subjects.
Jeremy has a special interest in Australasian plants (and is Secretary of the Australasian Plant Society http://www.anzplantsoc.org.uk in the UK, one of the few specialist plant societies actually growing in membership). Many of these, especially woody species, can prove tricky to propagate, and a novel method which is said to be remarkably successful is 'Aeroponics'. This intriguing method reverses overhead mist propagation by creating the same environment below the roots. It is relatively expensive and he is yet to test this out but it will prove an interesting subject to report back on in a future meeting.
He also described the value of bottom heat ('cool top/warm bottom'), and more sophisticated systems such as mist propagation and a 'Dewpoint' cabinet, but which many amateur growers are less likely to have access to, and touched on the use of rooting hormones.
We grow a much wider variety of plants on the nursery and garden and have developed a more traditional, simple and uniform system for reproducibility and economy. Gillian now uses a mix of equal parts of propagation grade Melcourt composted bark, fine perlite and sharp sand as a cutting compost, topped with pure sharp sand for the smallest of alpine cuttings. Most cuttings are kept in plastic domed propagation boxes, regularly sprayed by hand and checked for fungal infection, and carefully shaded in a reasonably cool greenhouse. The complexity of growing a wide variety of plants means that methods have to adapted and fine-tuned for different subjects, which can only come from experience and close observation.
Amongst the cuttings in the picture above are daphnes, silver saxifrages, the African Othonna cheirifolia, which has always proved a particular challenge to root well, and leaf cuttings of Eucomis and Ypsilandra. Gillian also looked more closely at the timing of taking different cuttings and then weaning rooted plants on before potting and growing away.
Propagation is a huge subject with many ramifications and a great deal of experiment and sometimes mystique. Not only is it central to the garden and any plant society it is also very rewarding and creative, so we will certainly be having many more meetings like this in the future, delving in more detail into specific techniques and new experiences.