Propagation of Deciduous Azaleas
by Alleyne R. Cook
Having selected and named the very best of the seedlings the next problem is how to produce them in sufficient quantities to supply the market. With deciduous azaleas only two ways are possible, these being by grafting or by the establishment of permanent stool beds and from them layered plants.
I shall deal first with grafting, the method employed on a tremendous scale by the Dutch nurseries. Its greatest advantage is the number of grafting scions that can be removed from a single stock plant so allowing a greater number of saleable plants to be produced in a short time. In fact there is no need for ground to be taken up by stock plants for grafting wood can be taken from the plants growing in the nursery rows.
The great disadvantage of grafting is the suckers that can come at any time in the plants life. The main idea of any grafting is to give the scion wood a growing base until it has developed its own roots which will come if the graft is planted under the ground. It would be thought that with the scion on its own roots the stock would become practically dormant but the stock always used is R. ponticum and years after planting for no apparent reason vigorous suckers will come which in a very short time will dominate the entire bush.
R. ponticum is a very lovely shrub which is scorned by gardeners because of the smallness of its flowers. It has a very vigorous constitution, it will grow in conditions that are not always favorable and it has a scent that none of the large flowered hybrids have. It is worth growing for this scent alone. The seedlings germinate very easily and because of its vigor grow to graftable size very quickly. It is a pity that this natural vigor produces the suckers that destroy the new plants.
The best example of how an Azalea Dell is being destroyed is the one at Tower Court shown on the cover of the 1948 Rhododendron Year Book. Looking at that picture it is hard to imagine that many of the varieties are being choked by suckers. From a distance the Dell makes a wonderful show of colour but when I inspected them more closely I was so disappointed in the individual bushes and the size of the truss and flowers that I left without taking one photo. These plants are of considerable age but they have been neglected since the beginning of the war so that there was nothing to force the suckers to grow such as damage with a spade.
Most English nurseries of repute dislike grafted plants for this reason and prefer to give their customers a better service by establishing permanent stool beds and selling plants on their own roots.
The great disadvantage is the time taken to establish a stool ground and the space it takes in the nursery. However when it is realized that a stool after it has been down 10 years will be producing up to 100 layers a year, as those at the Sunningdale Nurseries.