Fascination of Propagation

New Zealand Herald, Volume LXXVI, Issue 23333, 29 April 1939, Page 10 (Supplement)

Fascination of Propagation

COME strolling through garden',, probably found a small branch,-thair blown off by-stone' fiudden gust of wind, had fallen, end or , into soft mud. This had fomad'freshroot and started to grow. Being < ari intelligent being he would reason that ■ there was no- reason why other shoots,. similarly broken off, shoulitj: not grow also. As, however, he did riot write to the garden editor about it we have no written record of the first attempts at raising plants from cuttings. Nature, indeed, forestalled all the attempts of man in methods ofVplant propagation except budding. This, after all, is only a refinement of . grafting.- • Strangely enough, those great gardener^; the Chinese, did 11 Qt .ceach this .refinement until their contact with western civilisation. Layers, divisions, grafts and cuttings of stems, roots —examples of all of these ■ may be found in a country walk. The work of man has been simply to extend the methods of increase found in naturo and apply them to the vast numbers of plants! now grown iri gardens. In this, iby virtue or trial ana error, aided in 110 snutfll measure by the intuition which goes /With a "green thumb," he has

Always Room for Fresh Discovery

been very successful. Results that might well j\maze the novice are now of everyday occurrence. On 6 of the most important factors of Successful plant propagation is choosing the material at the proper stage. Some plants are easy enough to propagate in one month, but difficult or impossible in the other eleven. One part of a plant can be used successfully and no other. Microscopic examination has shown that some plants, off which the willow is a notable example, begin to form roots 011 their shoots quite early in their growth. These root initials retain their power of growth for so many years that it is not uncommon for a post to take root and form a tree. Black currants similarly form roots early, and this has suggested the method of using soft wood cuttings instead of those of old wood. There is a manifest advantage in this, for young shoots are less likely to be diseased than older ones, and the method is now in use to prevent infection by "big bud." Examination has also shown that delayed ripening of shoots may assist root formation, so that where plants prove very difficult to root from cuttings, it may be worth while to keep part of the stem (not the leaves) in the dark for a while before it is severed froth the plant. This is called epilation.

These investigations have not vet enabled us to predict with certainty what plants will root readily or not at all, and when they will root best. The gardener lias still to make trials before these questions can be answered, but the experienced propaeator is usually able to make a shrewd guess. Those who study the ways of plants observed, long ago, that roots turn away light, while stems and leaves turn towards it. In other words the intact plant is able to regulate and direct growth to the best advantage. How is this done? Man is fortunately not always content to sit in the sun and say, "How wonderful." A few men retain their boyish desire to "see how it works."

After much time and testing it was found that something made in the leaves is passed down to the plant's lowest parts. This is not the whole complicated story, but is in effect what appears to happen. Perhaps some of those organic manures which time has shown to be so potent, in their decay produce minute quantities of growth, producing substances and so give better results. Perhaps these root inducing growth substances always try to get to the lowest part of a shoot, and so cause the tip of the blackberry sucker to root. There is no end to the speculations tho discovery of these growth substances give rise to. It is a wonderful field for investigation.