CHAPTER IX

TOWN PLANTING, AND THE TREES AND SHRUBS THAT ARE BEST ADAPTED FOR SMOKY LOCALITIES

Probably no work connected with horticulture requires more judgment and good management than the planting of trees and shrubs in urban districts. The materials and soil of which streets and town gardens are usually formed are ill-fitted for maintaining a healthy condition in trees and shrubs for any length of time. This fact, coupled with the impurities of the atmosphere in densely populated centres, has to be constantly borne in mind. In more favourable districts all that is necessary is to open a pit of sufficient size to contain the roots of the tree or shrub to be planted; but in towns the soil, often as hard as iron and composed mainly of refuse building materials, contains but little plant food. For many years past careful observations have been made, not only in London, but in Glasgow, Liverpool, Manchester, Warrington and Dublin, as to which trees and shrubs succeed best in the smoky localities of each town, and it is mainly by tabulating these different experiences that satisfactory information on the subject has been obtained. Coal smoke from the chimneys in the larger and more crowded centres of industry is no doubt bad enough, but, when we have to contend with an atmosphere that is largely impregnated with the outcome from chemical, gas, or iron works, the difficulties to be encountered are correspondingly increased.

The injurious effects of smoke have become much more pronounced during the past century, and Sir William Richmond, R.A., told the annual meeting of the Coal Smoke Abatement Society that Westminster Abbey had suffered from more rapid decay in the last hundred years than in all the previous centuries of its existence. The chief cause of the destruction of the stonework has been shown to be the presence in the air of sulphur acids: the stone is converted into sulphate of lime; in the process of its formation this disintegrates the stone by expansion. The connexion between smoke and stone decay appears to lie in the action of invisible gases emitted from the smoke particles.

If stonework suffers so at the hands of smoke and sulphuric and other acids, what, it may be asked, must the effect be on the foliage of trees and shrubs—particularly such as are planted in the most smoke-infested parts of our great towns and cities? When compared with Continental cities—Paris, Brussels or Berlin—where tree-culture is carried out most successfully, the atmosphere of British towns is impregnated to a far greater extent with noxious fumes. Dry low-lying and confined areas, particularly where excessive heat and atmospheric impurities are present, are decidedly the worst, while open and high-lying districts, though in the centre of a town, offer fewer difficulties.

That certain trees and shrubs succeed best in particular towns is a well known fact, and the smoke-proof London Plane is by no means the best tree for some of the colliery districts; in Sheffield, for instance, its place is largely taken by the Canadian Poplar. In Manchester, the Lime would appear to thrive best, after which the Elder, Thorn and Plane succeed in the order named. The variegated-leaved Sycamore and the horse chestnut are favourites where the smoke from collieries is most offensive. But many such cases could be pointed out, and even in the case of bedding plants certain species succeed best in particular localities. In the gardens about the Royal Mint, where they are exposed to the deleterious fumes from gold-refining works, Fuchsias do remarkably well; indeed, the dwarf edging variety, Golden Treasure, thrives so well that advantage has been taken of the fact to propagate some of the stock that is annually required for one of the London parks from cuttings taken at the Mint. In the East End of London the Creeping Jenny (_Lysimachia_) thrives well as a window plant, while in the chemically impure atmosphere of Lambeth one of the Veronicas is the favourite plant for indoor culture. The St. John’s Worts (_Hypericum_) do not as a rule thrive well in London; yet around the Tate Gallery, which is only divided by the river from the Lambeth pottery district—the worst in the metropolis for atmospheric impurities—one species at least flourishes amazingly, and has produced flowers in abundance for many years past; while at St. Paul’s Churchyard, the lesser Periwinkle (_Vinca minor_) has become quite established and runs about freely. In Chancery Lane, at the Record Office, the common Ivy, Bladder Senna, and Yucca do best. In other parts of London, too, well known varieties of Campanula are largely grown as pot plants. It is a somewhat strange fact, too, that some varieties of trees and shrubs succeed better than the type species in smoky localities, as witness the London Plane (a variety of _Platanus orientalis_), variegated-leaved Sycamore, fastigiate Poplar, two varieties of Pyrus, Weeping Elm, Weeping Ash, and several varieties of Acacia, notably _Robinia pseudo-acacia inermis_ and _R. pseudo-acacia Bessoniana_.

Similarly, amongst shrubs, we have the dwarf Holly, golden variegated Euonymus, golden Privet, Ribes, double-flowered Gorse, _Euonymus radicans variegata_, and others. With Grasses, too, some curious experiences might be related. At the British Museum the Yarrow completely ousted the Grasses from the plots in front of that building, and in the moat of the Tower of London several Grasses that succeed in less smoky parts of the metropolis quickly die out. Near the main entrance to the Tower of London, and close to Billingsgate Fish Market, considerable difficulty was experienced in getting the Plane trees established; though in the matter of soil, and choice of strong sturdy specimens, every possible care was taken. At last it was found that the drip from the fish carts was the cause of the evil, and a remedy was quickly found. In another garden, where dust, smoke, and soot are plentiful, the Bladder Campion (_Silene inflata_), _Saponaria officinalis_, the common Marigold, and Rye Grass seem positively to revel. In situations almost constantly subjected to the sulphurous fumes of the railway engines near Camden Town, and in the poorest of soils, _Poa annua_ would appear to be quite at home. The chemical fumes from the pottery works at Lambeth are well known to act injuriously on vegetation generally, but the Mulberry, Fig, Sycamore, Turkey and Evergreen Oaks thrive as well there as they do in any part of the metropolis. The fumes given off from many of our city manufactories act most perniciously on vegetation generally—a fact that was brought to my notice by the behaviour of some of our most valuable smoke-resisting trees and shrubs planted in the graveyard at St. Giles-in-the-Fields. Meeting the gardener there I remarked on the wretched condition of the trees and shrubs generally, his quick reply being, “Well! with Crosse & Blackwell’s on the one side, and Nixey’s Black Lead Works on the other, it’s a wonder there’s a living plant left!” Here the common Fig and Black Poplar seemed better able to withstand the atmospheric conditions than either the London Plane or Acacia. With the largely increased use of coal gas for cooking purposes, improved grates, and the better combustion of fuel, the atmosphere of certain districts of London, has, however, become much less smoky than was the case a few years ago, and in consequence vegetation generally succeeds better. This is especially the case in some of the low-lying districts adjoining the Thames where the “slot” system of providing gas for cooking purposes has caused a great decrease in the consumption of coke and coal, with a corresponding reduction of the attending evils of smoke and soot. In one of the poorest parishes many of the inhabitants have taken advantage of the facilities offered by the Gas Company in the matter of cooking by means of gas provided by the “slot” system, which, in comparison with coal, has been found not only cheaper, but cleaner and handier to use. According to a competent authority the smoke nuisance has, in consequence, greatly abated, and with the purer air, the cultivation of window and other plants, as well as of trees and shrubs, has been to some extent simplified. The electrification of the Underground Railway has also had a beneficial effect on vegetation. Although we cannot prevent fog, which is an atmospheric condition, yet much can be done to prevent it being a dirty fog, and during the past five years much has been done in that direction. Better roads with less dust also assist largely in keeping the atmosphere of London in a pure condition.

With the rage for coniferous trees which was at its height about half a century ago, it is not surprising that several species of Cypress and Cedar, the stately Pines and Arbor vitæs, as also the Araucaria and Junipers, found their way into our town gardens and squares. Hosts of evergreens, too, from almost every part of the world were introduced into London, but few have been able to survive the smoky and otherwise impure atmosphere of the great metropolis.

Deciduous trees and shrubs, both flowering and ornamental-leaved, should certainly be regarded as the _sine qua non_ of the London planter. Amongst evergreen trees few are suitable for town planting, and, though a limited number of evergreen shrubs may succeed for a time, yet the list of deciduous species is far more extensive. We have only to take notice of such evergreens as the Holly, Rhododendron, Laurel and all the conifers, with probably one exception, to find how useless it is to plant them in expectation that they will give satisfaction. This is not hard to account for, as in winter, when the fires are all alight and smoke and soot the order of the day, the leaves of evergreens are fully developed and in the best possible condition for reaping the attending disadvantages. With deciduous species the case is quite different, for these are, so to speak, asleep when the deadly smoke and vapours are most abundant in our towns and cities. I am quite aware that one occasionally sees evergreen shrubs and trees in a fairly thriving condition; but it should be remembered that in the majority of such cases they were planted when conditions were much more favourable than at present.

It is, perhaps, to be regretted that evergreen shrubs do not succeed better in smoky localities, being planted principally for their refreshing colour in winter; but if our atmospheric conditions utterly preclude the use of such, then it is folly to throw away money on useless planting, and the winter aspect of deciduous trees and shrubs is infinitely preferable to that of unhealthy evergreens. The bursting into leaf of the deciduous tree or shrub is not shared to a like extent by evergreens, which lack that delightful changeableness and the interest that is attached to spring growth.

It is difficult to define accurately the boundaries of a town or the worst smoke-infested areas, as far as tree and shrub growth is concerned. In London, for instance, certain trees and shrubs which positively refuse to live in the heart of the city do fairly well in the suburbs, while still further out, where the atmosphere is comparatively pure, they may thrive in quite a satisfactory way. These thriving and non-thriving areas are sometimes very sharply defined, and this has given rise to a false idea regarding certain trees and shrubs that will rarely succeed in the more smoky parts when compared with the same species which are found to do well in the outer suburbs. High-lying and fairly open parts of a town are also far more conducive to plant growth generally than those that are close and confined. In town planting there is, however, no necessity for the almost monotonous repetition of such trees as the Plane and Lime, or amongst shrubs, of the Privet and Lilac, for there are many others that will do almost equally well, and that are quite as ornamental. Probably the fact that such are not well known would form an excuse for their absence, and it is to be hoped that at least one object to be accomplished by the writing of this book will be a greater interest in, and wider knowledge of, the various species of trees, shrubs, and plants generally that from long experience have been found suitable for planting in the town garden.

=Preparation of the Ground.=—Generally speaking, the materials with which roadways are made are not only unsuitable for tree cultivation, but positively destructive to vegetation of almost every description. This also applies to our squares, terraces, and open grounds around houses, the soil of which is little other than refuse building materials, and mainly composed of broken bricks and stones, gravel, old mortar, iron, wood and shavings. In such a medium it is perfectly useless to look for that healthy and vigorous growth which is so essential in street trees, that are still further handicapped by having to do battle above ground with the impurities of a town atmosphere.

Having for a number of years had to plant trees and shrubs in many parts of London, it was found that in nearly every instance substituting good soil for that found naturally was a first necessity. Many failures in street planting from this neglect of providing suitable soil could be pointed out, the result being that a section of the public has become tired of the subject in consequence of the initial expense and subsequent failures. Too often, also, the important operations of preparing the ground and planting the trees are left in the hands of the surveyor or builder, who has little or no knowledge to fit him for the work, the operation being carried out by labourers who are also entirely ignorant of what is required or the conditions necessary for successful tree and shrub culture. The consequence is that failure is almost certain, and the trees which were strong and healthy when planted gradually become unhealthy and ultimately succumb to a combination of circumstances which were brought about by the ignorance of the operators.

Another source of failure in street planting is the generally pent-up condition of the roots, for in several cases that have come under our notice lately the planter seemed to think that it was quite enough to cut a small hole in the pavement or street of sufficient size to hold the roots of the tree to be inserted. Were the soil free, as we find in a field, this system might answer; but where the roadway is hard as iron and composed mainly of clinkers and gravel, the case is totally different. Another fruitful source of failure in street planting is placing the pavement in too close proximity to the stem of the tree, and numerous instances could be pointed out where even old and established specimens have suffered irreparable damage in consequence of having the paving brought up too close to the stems.

The roots should always be allowed plenty of breathing room, and to affect this a good-sized space should be railed off around each tree and no pavement laid within it. Gratings may be placed on the surface of the ground around the tree, should circumstances compel such a course. By adopting either plan, a double benefit to the trees is brought about by allowing free access of water to the roots and preventing an accumulation of noxious gases in the soil, as would ensue if the flagstone or pavements were used.

Where street trees are to be planted, the ground-surface should in every instance be thoroughly broken up for a space of not less than 8 ft. square, and to a depth of, say, 4 ft., the inferior soil removed and replaced by that of good quality, preferably of a loamy description, or loam and leaf soil in about equal proportions. Before placing the fresh soil in position, the sides and bottom of each pit should be thoroughly loosened with a pick or fork. By undermining the sides of each pit, a much larger and freer root run will be provided, and this will not necessitate so much of the street or pavement being torn up as if the pits were of equal width at the top and bottom. We have found, in London at least, that the addition of a small quantity of leaf soil to the loam is highly beneficial to the growth of trees by retaining dampness and encouraging root spread. The newly added soil should be firmly trampled in the pit before planting is engaged in. Sometimes, where the original soil is not of too inferior quality, a small proportion has been mixed with the loam and leaf soil, but, speaking generally, this course cannot be adopted.

In squares and gardens where shrub planting is to be engaged in, a general renovation of the soil is also imperative, and this can best be done by thoroughly trenching the soil to a depth of, say, 4 ft. and adding a large proportion of fresh loam or other soil. Deep trenching and thoroughly breaking up and loosening the soil is a most important factor in town planting, and should never be neglected. Manure is sometimes added to the soil, but it is objectionable from several points of view, and, if used at all, should be thoroughly decomposed and incorporated in small quantity. Good loam and leaf soil is infinitely preferable, and, where necessary, sandy soil makes a good addition. A little fresh lime added to the soil has been found most beneficial in town planting, and in old and exhausted borders, where the soil has become tainted with chemical impurities, the value of lime or chalk as a cleansing agent is not sufficiently appreciated. Of course, where so-called American shrubs are to be planted—which is, however, rarely attempted in London—neither chalk nor lime should be added to the soil. This question of soil is so important that no one planting street trees or shrubs can afford to ignore it, and while the extra cost in providing it is but little, the advantages gained are great.

=Preparing the Trees and Planting.=—Trees intended for planting in towns, and especially alongside streets and footpaths, should be specially prepared in the matter of transplanting and pruning. As tree guards are a necessity in protecting trees by the sides of streets, the trees must have their stems free of branches; therefore the buds and branches on the stems need to be removed for a distance of 6 or 7 ft., whilst surplus leading shoots and ungainly branches should at the same time receive attention in pruning. The tree also needs to be frequently transplanted in order that an abundance of fibrous roots may be produced, and every effort made to produce healthy, vigorous specimens suitable for the uncongenial surroundings of their permanent quarters. In street planting it is advisable to use trees that are from 12 to 14 ft. in height; and if these, for some years previously to their final shift, have been specially prepared in the way of frequent transplanting and careful pruning, little fear for their future welfare need be entertained. Autumn or early spring planting is to be recommended, the former time being in most cases preferable. As little time as possible should be allowed to elapse between the lifting of the tree in the nursery and its being transplanted in the new position. Spread the roots out to their full extent around the stem and avoid planting too deeply; the nursery mark on the stem serves as the best guide as to the depth at which to plant. Planting too deeply under the mistaken idea that doing so will secure the tree in the ground is a fruitful source of decay and ultimate death of many street trees planted in the metropolis, and it is not uncommon to see whole avenues of trees that have made little or no progress for many years owing to this cause. After a tree has been placed in an upright position on the prepared site and the roots properly disposed, the soil should be filled in and trampled firmly both amongst and over the roots. It may be well to warn planters against the pernicious practice of allowing leaves, packing materials, or grassy turf to come in contact with the roots of newly-planted trees. In dry situations a saucer-shaped hollow may be left around the stem of the newly-planted tree, while mulching applied during dry and warm summers is to be recommended. The planting of shrubs should be carried out with as much care as is used in the case of trees. It is preferable to trench land in which shrubs are to be planted rather than to make a separate pit for each shrub.

Street trees should be carefully matched—that is, those of similar height and shape used in the same street. Too often this principle is not observed, as in a new street near the Strand, where some of the specimens are about 10 ft. high, others, 15 ft. and 20 ft. high—forming a very irregular, badly matched row. Many newly-planted town trees are destitute of leading shoots and have ungainly side branches—faults that should never be permitted when choosing specimens for such an important purpose. In choosing trees for street planting, the following rules should be observed:—

1. Stout, healthy, well-rooted and recently transplanted trees should alone be chosen.

2. They should, for the same street, be of nearly equal height and branch spread.

3. Straight-stemmed trees, with stout leading shoots, are to be preferred.

4. The height should range from, say, 12 ft. to 14 ft. or over, and the strength of stem should be proportionate to the height.

5. Trees with wand-like, crooked, or cankered stems should be avoided in street planting.

6. They should be beautiful, shade-giving, and easy of culture.

=Fencing and Staking.=—In order to prevent damage, newly-planted trees should be fenced and staked at once. Of fences or guards there are many kinds: they are made of wood, wire or iron. The iron tree guard has many advantages over those of wood or expanded metal, and, being made in two sections, it can be readily placed in position after the tree has been planted. For trees from 12 to 14 ft. high the guards need not exceed, say, 7 ft. in height, and preference should be given to those in which the uprights are bent outwards at the top; for this not only lessens the risk of interference with the branches, but is pleasing in appearance. Sometimes it may not be considered necessary to protect town trees, particularly such as are growing in side streets, or in squares, but in every case firm staking is necessary in order to prevent damage from wind.

Wooden tree guards consist of about half a dozen poles or uprights, about 7 ft. long, joined together around the tree trunk by means of wire. When compared with those of iron, they have, however, several disadvantages; for they may be climbed with ease and they do not last long. Where it is found sufficient to stake the trees without having recourse to guards, ash poles, from 2 in. to 3 in. in diameter, and 10 ft. high, should be driven firmly into the ground as close to the stem as possible. The tree should be tied with specially prepared tar rope, which should be crossed between the stem and stake to prevent damage by chafing. From time to time it will be necessary to see that the band of string does not become too tight. On rare occasions only is it necessary to stake shrubs, but this is sometimes advisable in exposed positions or in the case of shrubs of unusually large size.

=Watering and After-Management.=—For a few years after being planted, trees and shrubs will require a certain amount of attention in the matter of watering and mulching during the prolonged heat and drought, and also in preventing the evils attending excessive wind-swaying owing to the stakes and moorings becoming defective.

The goat and wood leopard moth, as also numerous kinds of caterpillars, attack newly-planted town trees, particularly the various species of Pyrus, Thorn, Willow and Poplar. The former tunnel into the main stem and render it so weak at the point attacked that it readily breaks across during windy weather, while the caterpillars feed on the foliage and greatly impair the health of the trees attacked. Spraying, hand-picking and shaking are to be recommended in the case of the caterpillars, while, to combat the goat and leopard moth, a small quantity of cyanide of potassium can be inserted in the mouth of the tunnel in order to dislodge or kill the insect.

Watering should preferably be performed in the evening, the ground around the roots being thoroughly soaked, while mulching with freshly-mown grass or old straw will prevent the too rapid evaporation of the moisture. In extreme cases binding the stem with a hay rope is to be recommended. In order to prevent straining of the roots and bark chafing, the moorings of trees should receive a periodical examination.

The following trees and shrubs are to be recommended for town planting:—

[Illustration: PLANE TREE IN REGENT’S PARK]

TREES

The =Oriental= or =Common London Plane= (_Platanus orientalis acerifolia_).—This variety of the oriental plane stands first in the category of select town trees. Not only does it grow vigorously in towns, but it is peculiarly well adapted for withstanding smoke and other impurities of the atmosphere. Repeated experiments have clearly proved that in London this tree flourishes better than any other, and a visit to the Thames Embankment and several of the urban districts will substantiate the statement; while the fine old tree which still exists in Cheapside, and the equally beautiful specimen which has hardly room for perfect development in the Court of Stationers’ Hall, Ludgate Hill, afford other examples of how well suited this handsome tree is for doing battle with the adverse conditions peculiar to the great metropolis. As a diversity of opinion has existed about which variety of plane it is that grows with such vigour in and around London, it may be stated that, on a careful examination of a large number of specimens, the variety _P.O. acerifolia_ was found not only more commonly distributed, but, likewise, better suited for town planting than the typical _P. orientalis_. This valuable variety is readily distinguished from the normal plant by the less deeply divided leaves, and from the American plane (_P. occidentalis_), with which it is sometimes confounded, by the many fruit “balls” which are attached to each peduncle, the fertile catkins of _P. occidentalis_ being, for the greater part, produced singly.

But not only for its value as a town tree is the oriental plane much sought after, but the giant proportions to which it attains, coupled with the handsome, finely-cut leaves and easy habit of growth, render it one of our most desirable ornamental trees. Further, it is of the easiest culture, succeeding extremely well in soils of very opposite qualities. Taking everything into consideration, we question whether any other of our forest trees is equal in value to the plane for purposes of town planting.

The =Maidenhair Tree= (_Ginkgo biloba_).—The maidenhair or ginkgo tree is one of the most valuable that can be planted in the impure atmosphere of a town garden. Few trees can compare with the one in question for withstanding the deleterious effects produced on vegetation generally by coming in too close contact with the impurities of our great centres of industry. The ample delicate-green foliage betrays—even late in the season, and when about to be cast off—little evidence of the fierce struggle that must almost constantly go on between vegetation and the smoke and filth of our towns and cities. That the thick, leathery leaves and strong constitution of the tree play an important part in keeping it free from disease is clearly evident, while the annual renewal of the leaves enables it to cast off the sooty nodules which work such havoc on the tender foliage of most evergreen trees.

At several places in and around the great metropolis—and in places, too, where one is almost stifled with the fumes from chimneys—this tree may be seen in almost as fresh a condition as those in the open country.

The =Ailanthus= or =Tree of Heaven= (_Ailanthus glandulosa_) may be seen in a very flourishing condition in many of the largest centres of industry in Southern England. It has been largely planted in many Continental cities, and has proved itself one of the few trees that is capable of withstanding the impurities of a town atmosphere.

The =Black Italian Poplar= (_Populus monilifera_).—Next to the plane amongst forest trees I consider the black Italian Poplar to be the most valuable for planting in smoky towns. As a proof of this there are to be seen numerous fine specimens of this tree in a flourishing condition, and clothed with the most healthy foliage, in some of our large cities—to wit, London, Glasgow, Liverpool and Manchester.

The =Canadian Poplar= (_P. canadensis_), and its variety, _P.C. nova_, are excellent trees for planting in smoky localities. The former succeeds admirably in the very centre of Sheffield, in the old parish churchyard, where for hundreds of yards around not a particle of living vegetation is to be seen. The variety _nova_ is a very superior tree for street planting, it being far more ornamental, and of more rapid growth than the black Italian poplar, and equally noticeable for retaining a healthy and flourishing condition under the adverse circumstances connected with a town atmosphere.

The =Abele Poplar= (_P. alba_) grows with great freedom when subjected to smoke and foul air. In the very heart of our largest towns it may be seen flourishing in a manner that is almost incredible.

The =Lombardy Poplar= (_P. fastigiata_) is another tree that has been planted with some success in and around many of our largest cities, but it cannot equal any of the foregoing for withstanding the baneful effects of a tainted atmosphere. In the outskirts of towns, where air is purer than amid chimneys pouring forth their volumes of smoke, the Lombardy poplar succeeds fairly well, and imparts an air of grandeur that could hardly otherwise be obtained.

The =Cucumber Tree= (_Magnolia acuminata_).—Few planters are aware of how valuable this tree is for withstanding the germs and soot of large towns. Experiments have, however, resulted in this highly ornamental tree being added to the list.

The =Tulip Tree= (_Liriodendron tulipifera_).—Excellent examples are not wanting of how valuable a tree this is for towns and streets. It seems to have a wonderful recuperative power, for, scorched, blackened, and encrusted as may appear the falling foliage, yet in the following spring it again puts forth a garb of the freshest and richest greenery. The remarkable four-lobed, truncate leaves render the tree almost without an equal for ornamental planting, while its undoubted smoke-resisting qualities place it high in the rank among town trees.

The =Indian Bean= (_Catalpa bignonioides_).—For various reasons this fast-growing tree is to be recommended for planting in smoky localities. It grows with great vigour in many smoky centres of industry, is a tree of handsome proportions, and, when fully established, flowers freely.

A valuable trait in the character of the Indian bean is that should accident befall it, and the stem get injured, numerous strong suckers are produced, which, as they grow with great rapidity, soon take the place of the original.

The =Common Mulberry= (_Morus nigra_) and the =white-fruited Mulberry= (_M. alba_) may be seen growing satisfactorily in several of the old gardens and nurseries of the metropolis, where they are now buried alive, as might be said, in stones and mortar. That they are excellent town trees will be admitted by every one who sees the fine specimens in Liverpool and Manchester.

The =Honey Locust= (_Gleditschia triacanthos_) is a very suitable subject for planting in smoky localities. In many of the worst smoke-infested parts of London and Manchester are seen goodly specimens of this handsome tree—not poor, miserable trees, but, from their great size, wealth of foliage, and general appearance, betokening perfect health amid their rather adverse surroundings.

The =False Acacia= (_Robinia Pseudo-acacia_).—Almost by the hundred can the false acacia be seen in London and many other English towns, thus proving that it is one of the most valuable trees that we possess for withstanding the injurious effects of an impure atmosphere.

What renders this acacia of greatest value as a town tree is that it retains its rich verdure till well on in autumn. The varieties known as =Decaisneana=, =inermis=, =microphylla=, =macrophylla=, =sophoræfolia=, and the upright-habited are most to be desired.

[Illustration: THE BEAM TREE IN LONDON]

The =White Beam Tree= (_Pyrus Aria_).—In many of the confined spaces in Glasgow the white beam tree grows luxuriously, and produces annually great quantities of its brightly-tinted berries.

The =Lime= (_Tilia europæa_).—Where the situation is not too confined, and where soot and smoke do not abound, the lime may, and does, succeed; but in the worst parts of the metropolis it soon shows signs of distress, the tops of the branches dying off, and the whole tree sooner or later showing the fierce struggle it has to endure with smoke and fumes. As an avenue tree in the more airy and pure parts of a town, the lime has certainly few equals, its general contour and the pleasing shade it affords being points of special recommendation.

The =Sycamore= (_Acer pseudo-platanus_).—This tree may be classed as amongst the most useful for planting in smoky towns.

In Warrington, where the noxious emanations from alkali and other chemical works are most disastrous in their effects on vegetation, the sycamore is one of the few trees that grow satisfactorily. Being a rapid and strong grower, it is thus seen to be, for a certain time at least, unaffected by its inimical surroundings. The variegated variety would seem from recent experiments to be preferable, and better adapted for smoky localities than the normal form.

The =Weeping Ash= (_Fraxinus excelsior pendula_) would seem to be superior to the common ash for planting in towns. It thrives satisfactorily in many of our largest centres of industry—to wit, London, Liverpool, Glasgow and Manchester.

The =Horse Chestnut= (_Æsculus hippocastanum_) may be seen in a fairly satisfactory way in many town parks, but only where it is not exposed to smoke and soot to any great extent. In confined spaces both it and the =English Elm= (_Ulmus campestris_) soon show signs of distress, the points of the branches gradually becoming unhealthy, and the trees dying off prematurely. Taking everything into consideration, neither of these trees can be recommended for planting in smoky districts. The =Birch=, =Walnut=, =Hornbeam=, and one or two kinds of =Willow= will succeed in the less smoky parts of a town; but they are not to be recommended for planting where the air is constantly impregnated with soot and dust.

The =Mountain Ash=, or =Rowan Tree= (_Pyrus aucuparia_) and =Bird Cherry= (_Cerasus Padus_) are both good town trees, and excellent examples of both may be seen in the back streets and slums of London.

=Sophora japonica= is well worthy of recommendation as a tree that is admirably suited for planting in towns. It is of large and rapid growth, with elegant dark green pinnate leaves. Being a native of China and Japan, it may not be perfectly hardy in the northern portions of the British Isles, but it succeeds well in Southern England, and thrives admirably in the most smoke-infested parts of London.

=Thorns= of various kinds succeed well in towns, but they must not be recommended for the most smoky and confined localities.

The =Tansy-leaved Thorn= (_Cratægus tanacetifolia_) is an excellent member of the family for town planting.

SHRUBS

Of these there is rather a long list of kinds that are suitable for planting in smoky localities.

Evidently deciduous species possess an advantage over evergreen kinds in the total annual renewal of their leaves, and hence it follows that, as with trees, deciduous shrubs should have the preference.

The following list includes only such kinds as have been proved suitable for town planting:—

=Osmanthus ilicifolius= is one of the handsomest of evergreen shrubs, and also one of the few that succeed, in a satisfactory way, when subjected to the impurities of a town atmosphere. In the smokiest districts of both London and Liverpool it is unquestionably the best all-round shrub.

=Ligustrum coriaceum= is a fitting companion to the last, so far, at least, as its powers of withstanding the effects of an impure atmosphere are concerned. Being an evergreen, it is peculiarly well suited for planting in the town garden, where it grows with great freedom.

=Olearia Hastii= and =O. macrodonta= are excellent shrubs for the London garden.

=Aucuba japonica.=—This well-known evergreen shrub is of great value for planting in urban districts, it being able to do battle with a more than ordinary amount of atmospheric impurities. For this reason it has been largely planted in town squares and gardens, in the most crowded and densely populated parts.

=Griselinia littoralis.=—Although a little-known evergreen, this is well suited for town planting, experiments having proved it to be a most valuable addition to the limited number of shrubs suitable for such a place.

=Hibiscus Syriacus= is one of the few shrubs that can successfully battle with an impure atmosphere. It is a shrub which town residents should plant freely if they have a bit of ground that they want to look pretty.

The =Warfaring Tree= (_Viburnum lantana_) does not receive that amount of attention to which on its merits it is entitled. It succeeds well in some of the most filthy and smoky districts of our largest cities.

The =Venetian Sumach= (_Rhus cotinus_) is a much-neglected shrub, but for general usefulness it can hardly be surpassed. It is peculiarly suitable for planting in cities.

The =Stag’s Horn Sumach= (_Rhus typhina_) must, on no account, be omitted, as it is a shrub of curious appearance and one that thrives well in soot and dirt.

=Leycesteria formosa= is a capital town plant; this may also be said of the =Flowering Currant= (_Ribes sanguineum_)—indeed, too much praise can hardly be bestowed on these shrubs for planting in the town garden and shrubbery.

=Skimmia japonica= and the =Snowy Mespilus= (_Amelanchier Botryapium_), too, succeed well in smoke-infested districts; and the various kinds of Lilac—particularly the Common and Persian—have few equals as town shrubs.

In the =Kentucky Coffee-Tree= (_Gymnocladus canadensis_) and =Bladder Senna= (_Colutea arborescens_) will be found two most useful shrubs for the town garden.

=Phillyrea Vilmoriniana=, =Forsythia viridissima=, and the =Strawberry Tree= (_Arbutus unedo_) are all more or less suitable for town planting where the atmospheric conditions are not too seriously affected by smoke and dust.

The =Double Furse= (_Ulex europæus florepleno_) is one of our handsomest flowering-shrubs, and a good addition to the list of such as are suitable for planting in town gardens and squares.

The =Spurge Laurel= (_Daphne laureola_) grows freely in many a town garden—indeed, it is no uncommon thing to see large and well-balanced specimens where smoke and filth are the order of the day.

=Cotoneasters= of various kinds succeed well as town plants. Those to be particularly noted are _C. frigida_, _C. Simonsii_, and _C. vulgaris_.

=Euonymus japonicus= is another excellent shrub, being almost smoke-defying.

The double-flowered forms of =Prunus sinensis= and the equally ornamental =P. triloba= all succeed well as town plants; while the =Almonds= are quite as good.

=Koelreuteria paniculata=, the =Laurustinus= (_Viburnum tinus_), =Weigelia rosea=, =W. amabilis=, =Deutzia scabra=, the common =Green Box=, =Gum Cistus= (_C. ladaniferus_), =Mahonia aquifolia=, =M. Bealii=, and =M. japonica= are all more or less suitable for town gardens, but not for those in the most smoke-infested parts. The =Japan Quince= (_Cydonia japonica_), =Hypericum Nepalense=, and =Euonymus radicans= all do well when subjected to the town atmosphere.

CLIMBERS

Of shrubs suitable for covering walls, trellises, and arbours, and able to resist the dire influences of smoke and soot, there are a few valuable and well-tried kinds.

The =Virginian Creeper= (_Ampelopsis hederacea_) has few equals as a town plant, thriving successfully in the midst of our busiest centres of industry. Many instances could be pointed out in which this handsome climber grows with the greatest freedom in the most impure and smoke-laden atmosphere.

The =Common Ivy= (_Hedera helix_) is, perhaps, the most valuable of all climbing plants for using in smoke-infested localities. In some of the courts near Ludgate Hill, a district of London that is by no means free from smoke and dust, the ivy climbs houses to a height of 60 ft., and surprises one by its fresh appearance in such localities.

The =Evergreen=, or =Trumpet=, =Honeysuckle= (_Lonicera sempervirens_) is another shrub of great merit for town planting, as it thrives well in confined spaces, and where the atmosphere is very impure.

=Cratægus Pyracantha= is a most valuable wall shrub for the town garden. It is of free growth, stands smoke well, and is one of the handsomest berry-bearing plants in cultivation.

=Jasminum nudiflorum= needs little description, as it is one of our handsomest wall-plants. For smoky districts it is invaluable, blooming freely when flowers are scarce, and seeming to heed but little the impurities of a town atmosphere.

[Illustration: THE SAVIN, OR JUNIPER, AS A TOWN SHRUB]

The =Vine= (_Vitis vinifera_) must not be omitted from our list, it being an excellent plant for withstanding soot, smoke, dust and heat.

CONIFEROUS TREES

Few of these, if any, succeed in a satisfactory way, when constantly subjected to the impurities of a town atmosphere.

Where the conditions are at all favourable the =Austrian Pine= (_Pinus austriaca_), =Thyiopsis Dolabrata=, =Toxodium distichum=, and =Cupressus Lawsoniana= do fairly well, but they are not to be recommended for general town planting.

=Retinospora plumosa aurea= has stood for many years in one of the most smoky districts of Glasgow, and at present looks almost as well as it did when brought from the country, while the =Savin= (_Juniperus Sabina_) may generally be relied upon.