The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
Shrubs And Trees
Factors Which Govern Hardiness
The ability or failure of a shrub or tree to survive the winter in one's garden, particularly the first that follows upon its planting, is not always simply a matter of the inherent hardiness of the kind involved. This is only one of several factors which govern the success or failure of a plantation. Let us review some of the others.
Any shrub or tree may come to grief in unsuitable soil. The hardiest of Rhododendrons and their relatives will fail unless the soil conditions described on p. 132 are met.
A very important factor is drainage, both of the surface and of the sub-soil. Water, collecting either above or below the surface between autumn and spring, spells almost sure failure with most of the materials described in this volume. A naturally moist but well drained soil is a boon, but stagnant soil creates one of the most difficult problems that can confront the gardener; and there is no solution for it except to provide drainage.
If stagnation is caused by underlying hardpan in otherwise drainable land, this layer must be broken up. If it lies sufficiently deep and is so tilted that water will drain off above it, it is not necessarily a fatal factor. If it lies close enough to the surface and is not too thick, a toothplow dragged through it may break it up sufficiently to let water through. If it lies deep, and moisture does not drain off above it, then dynamiting is the best way to deal with it. This need not be the violently eruptive sort of operation which the word suggests. People skilled at this work can do it in such manner as to cause scarcely any surface disturbance. When hardpan is present and drainage unsatisfactory, it will pay one who is about to plant a new place to employ expert skill at this business.
In fact, even when it is not necessitated by the presence of hardpan, skillful dynamiting provides a highly beneficial means of sub-surface cultivation, especially in heavy soils, too rarely practised. It should be done expertly and need not even ruffle the surface.
Generally, losses of shrubs and trees due to poor drainage are more common, even on high land, than one would suspect.
Hardpan has a way of resetting eventually, after it has been broken up, and the dynamiting operation may have to be repeated after a number of years.
Much less simple is the problem of providing drainage in low-lying land where stagnation is caused not by hardpan but by the natural water-table. Places like that are very difficult to plant successfully; and if there is any choice in the selection of a home site, this kind of situation should be avoided.
If the cost of raising the ground above the surrounding level is prohibitive, then one had better adapt the plantations as nearly as possible to the condition, selecting materials most likely to succeed in it. But the choice will be limited, and a high percentage of losses must be expected.
