This section is from the book "The Gardener's Monthly And Horticulturist V20", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
The Gardener's Chronicle gives the following sketch of some proceedings in Germany:
" Dr. Bolle recently communicated to the Horticultural Society of Berlin some interesting particulars of the relative hardiness of different trees in Germany. Species of Carya which succeed admirably in the Central States of North America suffer from May frosts. Pterocarya Caucasica survives, but only on dry soil. The Cedar of Lebanon, although it ascends to the snow region in its native country, is not perfectly hardy, whereas the Deciduous Cypress, Taxo-dium distichum, is not injured. The latter inhabits the Southern States of Northern America, and is one of the few instances of plants which will bear a climate colder than that of the country in which they now exist in a wild state. In his useful Book of Evergreens Josiah Hoopes says, 'The Deciduous Cypress, although strictly a Southern tree, thrives admirably in the climate of the Middle States. Its most northern natural limits are the Cypress swamps of Maryland, and the extreme southern part of Delaware. - Throughout every portion of the Southern States this tree is found in the low miasmatic swamps and occasionally very plentifully, especially along the borders of the rivers and larger streams.
Indeed, in the Gulf States these Cypress swamps cover thousands of acres, and along the Mississippi river particularly they extend for hundreds of miles.' Like the Arbor-vitte this tree sheds not only its leaves but also its ultimate branchlets, which may possibly explain its hardiness. The Mexican variety, of which a tree girthing 100 feet is said to exist at Chapultepec, is tender. Dr. Bolle thinks these peculiarities in the constitution of plants are governed by the distribution of heat in the different seasons of the year. One of the members present observed that deciduous shrubs generally withstand frost better than evergreens, because they are at rest in Winter, mentioning as examples Magnolia glauea and Larix Kaempferi".
It has long been known here that deciduous trees are hardier, and evergreens more tender in America than in Europe, as a general thing. Cur hot, dry Summers enable the trees to get rid of their surplus moisture; and, as they have little evaporating surfaces during Winter, what they have they keep. They have no excess to freeze and rupture the cells, and have accumulated heat enough and secreted non-congealable matter sufficient to prevent the freezing of what it has retained, while the evergreen is all the Winter long exposed to evaporating influences which dry out the moisture to an extent utterly unknown to the moist atmosphere of Europe, where people say deciduous trees are"at rest" in Winter, as compared with evergreens. It is hard to tell what is really meant.