The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California

Shrubs And Trees

To review the varying behavior of all these materials in the several latitudes would require a volume infinitely larger than the present. Thus, in order to keep this treatment within a handy, small volume, to avoid vague description and to achieve definement, it seems practical and conservative that we should deal with our materials as they behave in cultivation somewhere near the colder temperature limit indicated. To that end then, we adopt—not by way of a limitation to the usefulness of this book, but rather by way of a definite climatic norm—as "our zone," those parts of the United States where temperatures fall not rarely to 25 degrees below zero. This zone is well represented by the author's own locality, Poughkeepsie,

N. Y., where temperatures of 30 below are experienced only rarely.

This point on the map lies within the climatic band which is indicated in Rehder's Manual of Cultivated Trees and Shrubs as Zone V. The northernmost limits of our hardiness ratings, however, may extend somewhat, here and there, beyond Rehder's Zone V into the mildest fringes of his Zone IV. While no definite southern limits can be drawn, the scope of our volume may be understood to include at least all of Rehder's Zone VI.

Readers near the Northern limit are cautioned that in many localities there are low-lying cold spots so called frost pockets where comparatively low temperatures may occur and where tender flower buds like those of Dogwood and Forsythia may come to grief, while they may remain uninjured in upland situations. Other features as well, like drainage, may affect the hardiness of plant materials in particular places. One ought always to take account of local weather experience and of topographical considerations. See the chapter on "Factors Which Govern Hardiness."

Included in our evaluations are more than four hundred items of border and other shrubs, specimen materials, and a limited number of shade trees for small places. Nearly all, except the last-named category, have been included in the Score-Chart, which contains 363 listings.

The assortment includes the best of available deciduous materials for our specified purpose, both native and exotic kinds. They are evaluated strictly from the viewpoint of their serviceability, regardless of the geographical origins of the species. Considerations which tend to prefer native materials for roadside and parkway plantings need not enter into the choice of materials for the small domestic landscape. It would be very difficult, indeed, to forgo the use of such things as exotic Spiraeas and Shrubby Honeysuckles (Loniceras), nor is there any practical reason why good, exotic kinds should be excluded.