The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
Shrubs And Trees
Another factor is circulation of air. The comparatively still air in a natural, low-lying, so-called frost-pocket or, for that matter, in any inclosed area, will fall to winter temperatures lower than those prevailing in open spaces.
And apart from temperatures, many kinds of shrubs and trees appear to have a natural preference for unhampered air circulation. One finds striking demonstrations of this not only among the deciduous but also among evergreen materials. The American Arborvitae, for instance, will stand the worst of winter's blasts, in a totally exposed place, better dian the lee of a building or protective screen. And, while, to our continual humiliation, the Firethorn (Pyracantha) refuses steadfastly to survive the winters in our grounds, we find it thriving like the proverbial green bay tree in extremely exposed places some 17 miles to the North-east of us.
In the case of a number of shrubs indicated in our Review as not completely hardy in our climatic zone, it appears that they come through the winters more reliably when provided with at least light shade dian when fully exposed to the winter sun. This holds true, for instance, of Stephanandra, Neillia sinensis, and many odier shrubs. The value of protection from the winter sun is more generally acknowledged in the case of bodi broad- and narrow-leaved evergreens than in relation to the deciduous shrubs. Shade tends to lessen the development of autumnal or odier foliage color, but, insofar as shrubs are at all adaptable to shade, it also affords a measure of winter protection.
Certain shrubs and trees which are perfectly hardy in the long run are decidedly more tender in their early years. One of these is the Japanese Dogwood, Corntts kpusa, which we have known to suffer more or less serious winter-injury at Poughkeepsie, N. Y., in grades up to about 5 feet high, but rarely in sizes over 6 feet. One and two year old seedlings of our native Flowering Dogwood are likely to be injured, even on seedling beds, unless well protected; but older grades are perfectly hardy. That is why, in a number of instances, in our review of shrubs, we have suggested planting older, rather than young, grades.
But, apart from these environmental factors, much of the success of newly planted material in surviving its first winter depends upon the quality, the grade and the condition of the stock used.
Materials which are best dug with a ball of earth have been so indicated in the Classified Tabulations. The advantage of balling and burlapping ("B&B") is that the moving of an intact root-system, with an adhering clump of earth, lessens the shock of transplanting.
It should be understood, however, that this advantage prevails only when the earthball contains a clump of fibrous roots, to which the earth clings naturally.
