The territory for which this list has been prepared comprises that lying between the Atlantic Ocean on the east and the Appalachian foothills or Piedmont on the west, and extending from Washington, D. C, to Savannah, Atlanta, and southern Alabama. This territory includes the eastern half of Virginia and of North Carolina, nearly all of South Carolina and of Georgia and all of Alabama lying south and east of Birmingham (See Plate No. II).
Owing to the influence of the mountains on the west and north, and of the Atlantic Ocean with its Gulf Stream on the east, this territory is especially favourable for the growing of plants which would not succeed at the same latitude farther inland. This territory has a high annual average humidity and a rainfall of 50 to 60 inches each year. It has a low narrow range in temperature -about 30 degrees -and a long growing season, extending from one hundred and eighty days in the north to two hundred days in the south. All of these factors contribute to the successful growth of many somewhat tender plants and in some cases also force the growth of northern plants to a great size.
The most that can be done under present conditions with a list of this kind and until such time as further information is compiled, is to tabulate some of the more important types of plants which have been used throughout this southern territory. It must be remembered that with the much longer growing season and the higher average of rainfall plants will grow much more vigorously and much larger than the same plants will grow throughout the northern zones. Plants which may be adapted to a certain use in the zones farther north may be entirely inappropriate for a similar use in this southern territory. For this reason intimate knowledge should be obtained concerning the growing characteristics of any types that are to be introduced into the southern conditions.
Many of the plants adapted for use in the northern zones will readily produce an abnormal growth in these southern zones as represented by the south Atlantic states. On the other hand, very few of the plants which are indigenous to this south Atlantic area will prove hardy when used in the territory north of Washington. For instance, Hall's climbing honeysuckle is one of the plants common to both the northern zone and the southern zone, but in the southern territory this plant produces a much more interesting development of foliage and of flowers while in the northern zones the same plant suffers severely from winterkilling of the small and more tender portions of its growth. There are a few of our desirable northern types, such as lilacs, which adjust themselves with extreme difficulty to the changed climatic conditions. On the other hand, the hydrangea is grown with remarkable success in the south.
Plate L. A few water lilies may enhance a picture such as the above, but a proper restraint on their use and control is always desirable. (See page 234, group XXXI-L-a)
Plate LI. The artificial lake or pond may receive a natural effect if the banks near the water's edge are planted with groups of water-loving plants. In this picture one sees the marsh-mallow, day-lily, iris, plantain-lily, loosestrife, plume grass, and showy sedum successfully used. (See page 234, group XXXI-L-c)