Manual of Gardening Part 44

Noisettiana,_ are useful in the open in the South.

7. TREES FOR LAWNS AND STREETS

A single tree may give character to an entire home property; and a place of any size that does not have at least one good tree usually lacks any dominating landscape note.

Likewise, a street that is devoid of good trees cannot be the best residential section; and a park that lacks well-grown trees is either immature or barren.

Although the list of good and hardy lawn and street trees is rather extensive, the number of kinds generally planted and recognized is small. Since most home places can have but few trees, and since they require so many years to mature, it is natural that the home-maker should hesitate about experimenting, or trying kinds that he does not himself know. So the home-maker in the North plants maples, elms, and a white birch, and in the South a magnolia and China-berry. Yet there are numbers of trees as useful as these, the planting of which might give our premises and streets a much richer expression.

It is much to be desired that some of the trees with "strong" and rugged characters be introduced into the larger grounds; such, for example, as the hickories and oaks. These may often transplant with difficulty, but the effort to secure them is worth the expenditure. Good trees of oaks, and others supposed to be difficult to transplant, may now be had of the leading nurserymen. The pin oak _(Quercus pal.u.s.tris_) is one of the best street trees and is now largely planted.

It is at least possible to introduce a variety of trees into a city or village, by devoting one street or a series of blocks to a single kind of tree,--one street being known by its lindens, one by its plane-trees, one by its oaks, one by its hickories, one by its native birches, beech, coffee-tree, sa.s.safras, gum or liquidambar, tulip tree, and the like.

There is every reason why a city, particularly a small city or a village, should become to some extent an artistic expression of its natural region.

The home-maker is fortunate if his area already possesses well-grown large trees. It may even be desirable to place the residence with reference to such trees (Plate VI); and the planning of the grounds should accept them as fixed points to which to work. The operator will take every care to preserve and safeguard sufficient of the standing trees to give the place singularity and character.

The care of the tree should include not only the protecting of it from enemies and accidents, but also the maintaining of its characteristic features. For example, the natural rough bark should be maintained against the raids of tree-sc.r.a.pers; and the grading should not be allowed to disguise the natural bulge of the tree at the base, for a tree that is covered a foot or two above the natural line is not only in danger of being killed, but it looks like a post.

The best shade trees are usually those that are native to the particular region, since they are hardy and adapted to the soil and other conditions. Elms, maples, ba.s.swoods, and the like are nearly always reliable. In regions in which there are serious insect enemies or fungous diseases, the trees that are most likely to be attacked may be omitted. For instance, in parts of the East the chestnut bark-disease is a very great menace; and it is a good plan in such places to plant other trees than chestnuts.

A good shade tree is one that has a heavy foliage and dense head, and that is not commonly attacked by repelling insects and diseases. Trees for shade should ordinarily be given sufficient room that they may develop into full size and symmetrical heads. Trees may be planted as close as 10 or 15 feet apart for temporary effect; but as soon as they begin to crowd they should be thinned, so that they develop their full characteristics as trees.

Trees may be planted in fall or spring. Fall is desirable, except for the extreme North, if the land is well drained and prepared and if the trees may be got in early; but under usual conditions, spring planting is safer, if the stock has been wintered well (see discussion under Shrubs, p. 290). Planting and pruning are discussed on pp. 124 and 139.

If one desires trees with conspicuous bloom, they should be found among the magnolias, tulip trees, koelreuteria, catalpas, chestnuts, horse-chestnut and buckeyes, cladrastis, black or yellow locust, wild black cherry, and less conspicuously in the lindens; and also in such half-trees or big shrubs as cercis, cytisus, flowering dogwood, double-flowered and other forms of apples, crab-apples, cherries, plums, peaches, hawthorn or crataegus, amelanchier, mountain ash.

Among drooping or weeping trees the best may be found in the willows _(Salix Babylonica_ and others), maples (Wier's), birch, mulberry, beech, ash, elm, cherry, poplar, mountain ash.

Purple-leaved varieties occur in the beech, maple, elm, oak, birch, and others.

Yellow-leaved and tricolors occur in the maple, oak, poplar, elm, beech, and other species.

Cut-leaved forms are found in birch, beech, maple, alder, oak, ba.s.swood, and others.

_List of hardy deciduous trees for the North._

(The genera are arranged alphabetically. Natives are marked by (A); good species for shade trees by (D); those recommended by the Experiment Station at Ottawa, Ontario, by DD)

In a number of the genera, the plants may be shrubby rather than arboreus in some regions (see the Shrub list), as in acer _(A. Ginnala, A. spicatum_), aesculus, betula _(B. pumila_), carpinus, castanea (_C.

pumila_), catalpa _(C. ovata_), cercis, magnolia (_M. glauca_ particularly), ostrya, prunus, pyrus, salix, sorbus.

Norway maple, _Acer platanoides._(D, DD) One of the finest medium-sized trees for single lawn specimens; there are several horticultural varieties. Var. _Schwedleri_(DD) is one of the best of purple-leaved trees. The Norway maple droops too much and is too low-headed for roadside planting.

Black sugar maple, _A. nigrum._(A, DD) Darker and softer in aspect than the ordinary sugar maple.

Sugar maple, _A. saccharum._(A, DD) This and the last are among the very best roadside trees.

Silver maple, _A. saccharinum (A. dasycarpum_).(A, DD) Desirable for water-courses and for grouping; succeeds on both wet and dry lands.

Wier's cut-leaved silver maple, _A. saccharinum_ var. _Wieri._(D, DD)

Light and graceful; especially desirable for pleasure grounds.

Red, soft, or swamp maple, _A. rubrum._(A) Valuable for its spring and autumn colors, and for variety in grouping.

Sycamore maple, _A. Pseudo-plata.n.u.s._ A slow grower, to be used mostly as single specimens. Several horticultural varieties.

English maple, _A. campestre._ A good medium-sized tree of slow growth, not hardy on our northern borders; see under Shrubs (p. 291).

j.a.pan maple, _A. palmatum (A. polymorphum)_. In many forms, useful for small lawn specimens; does not grow above 10-20 ft.

Siberian maple, _A. Ginnala._(DD) Attractive as a lawn specimen when grown as a bush; the autumn color is very bright; small tree or big shrub.

Mountain maple, _A. spicatum._(A) Very bright in autumn.

Box-elder, _Acer Negundo (Negundo aceroides_ or _fraxinifolium_).(A)(D) Very hardy and rapid growing; much used in the West as a windbreak, but not strong in ornamental features.

Horse chestnut, _aesculus Hippocastanum._(D)(DD) Useful for single specimens and roadsides; many forms.

Buckeye, _ae. octandra (ae. flava)_(A)(DD)

Ohio buckeye, _ae. glabra_(A)

Red buckeye, _ae. cornea (ae. rubicunda)_.

Ailanthus, _Ailanthus glandulosa._ A rapid grower, with large pinnate leaves; the staminate plant possesses a disagreeable odor when it flowers; suckers badly; most useful as a shrub; see the same under Shrubs (also Fig. 50).

Alder, _Alnus glutinosa._ The var. _imperialis_(DD) is one of the best cut-leaved small trees.

European birch, _Betula alba._

Cut-leaved weeping birch, _B. alba_ var. _laciniata pendula._(DD)

American white birch, _B. populifolia._(A)

Paper, or canoe birch, _B. papyrifera._(A)

Cherry birch, _B. lenta._ (A)

Well-grown specimens resemble the sweet cherry; both this and the yellow birch (_B. lutea_(A)) make attractive light-leaved trees; they are not appreciated.

Hornbeam or blue beech, _Carpinus Americana._(A) Chestnut, _Castanea saliva_(D) and _C. Americana._(A)(D)

Showy catalpa, _Catalpa speciosa._(D)(DD) Very dark, soft-foliaged tree of small to medium size; showy in flower; for northern regions should be raised from northern-grown seed.

Smaller catalpa, _C. bignonioides._(D) Less showy than the last, blooming a week or two later; less hardy.

j.a.panese catalpa, _C. ovata_ (_C. Koempferi_).(DD) In northern sections often remains practically a bush.