This section is from the book "Commercial Gardening Vol1", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
From the earliest development of the leaf in spring, preparations are being made at the base of its stalk, whereby it will be thrown off in autumn in the case of deciduous trees and shrubs. This is brought about by the development of a layer of cork cells right across the stalk, exclusive of the vascular bundles. During the autumn, but especially in October and November, this layer of cork becomes completed by the maturing and dying of the cells, and it needs only a breeze of wind or a night's frost to snap the vascular bundles and bring the leaves down in showers. The leaves of the Ash are still quite green when this happens. This state of maturity in the leaves of the Peach is favoured by giving abundant ventilation both at the top and bottom of the house in the case of planted trees. Those in pots should be stood outside after the fruit is gathered. Pot Vines may be served in the same way. Established Vines that are tardy in dropping their leaves may be assisted to mature them by an abundant ventilation, with a dry atmosphere, and a gentle heat from the hot-water pipes. It would be unwise to hasten the process unduly by keeping them very dry at the roots.
Fig. 42. - Cephalotus follicularis.