All plants do not thrive in the same soil. So the soil of your garden will help to govern your choice. Is it dry, wet, or average? Is it acid, sweet, or neutral? Is the gar- den in full sun, partial shade, or all shade? These factors are important to the growth and well-being of plants, and each of them limits selection.

Unity Through Ecology

Since ecology is the study of plants in relation to environ ment selection based on habitat might be termed the ecologi cal method. Elsa Rehman and Edith Roberts wrote helpfully on this subject in American Plants for American Gardens.

They concluded that most plants live in societies based on similar physical requirements. Therefore a degree of garden unity can be secured by selecting plants according to environ ment.

Closely connected is the matter of climate and exposure. Today we use plants native to Asia, South Africa, South America, Europe, and the many sections of our own country too. This does not mean that they will all live and thrive in our gardens. To be intelligent about plant selection we need to know fairly exactly for a given locality the date of the last hard frost in spring, the first killing frost in autumn, and the lowest degree of temperature in winter. This information has a bearing on the varieties of plants we can grow. Most garden encyclopedias and dictionaries now have a geographical chart indicating climatic zones. Some garden books and catalogues also note degree of hardiness, for example, "Not hardy north of Philadelphia except with winter protection." No garden is successful if a large amount of the material in it is of ques tionable hardiness. Nor will it look like much in winter if it is full of trussed-up specimens, mounds of salt hay, clutters of leaves, or masses of evergreen boughs protecting tender plants.

Bad as this is artistically it is even worse financially for many of the more exotic plants, which are not cheap, often succumb the first winter, and there is added disappointment and a last-minute rush to fill empty spots with something more durable. We were all made conscious of hardiness a few years ago when an excessively cold winter robbed many northeast ern gardens not only of all tender plants but of many long considered hardy. Such winters are not normal but occur of ten enough to make it foolish to use plants of doubtful hardi ness in prominent places.