This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Among the many subjects which have been discussed in your valuable magazine, this is one which I think has not received due attention. I am sure there is no branch of gardening worse understood, or if it really is understood, not treated accordingly. I have worked in and visited many gardens, and have never seen flowering-shrubs on walls attaining to anything like perfection. The pruning they generally receive is done with the hedge-shears, clipping them close in to keep the wall tidy. This is what one might term a rough style of pruning on the spur system, of course allowing the terminal shoots to grow on and cover the wall. On these shoots I have seen a few flowers, but very rarely on any other part of the plant. This plainly shows that it is on the previous year's growth that the flowers are produced; thus it is obvious that spur-pruning is not the style. Of course that principle will suit some plants, such as Jasmine, Honeysuckle, and Clematis, which bear flowers on the same year's growth, but with shrubs such as Escallonia, Ceanothus, and Deutzia, I would say, nail in a fair amount of young wood each year and cut out the old, which would insure a return in the shape of flowers, for which purpose the shrubs were planted.
In fact one will generally find them filling the place of evergreen shrubs. If flowering-shrubs are wanted, let them be managed so as to produce flowers; if not, Ivy will cover a wall to more purpose, and besides can be kept tidy with less trouble.
In concluding, I would say this is not to instruct my readers how to manage these shrubs, but simply to bring the subject before your notice; and I would pray some one who has had more practice to give us a few hints as to their management, which I am sure would gratify the readers of the ' Gardener.' D. K.