Trees and Shrubs for English Gardens Part 7

When thinking of trees and shrubs in early spring we must remember those with beautiful catkins. Of the earliest flowering hardy trees and shrubs the majority are those with flowers borne in catkins. Their appearance is one of the first evidences of the approach of spring. It is to the catkin-bearing group that the Poplars, Willows, Birches, and Alders belong. These catkins are pendulous, cylindrical, and often slender inflorescences, carrying flowers of one s.e.x only, which spring from the axils of scaly bracts. Being mainly dependent upon the wind for their fertilisation, they have none of the varied or bright colours that are characteristic of flowers fertilised by insect agency. Often, indeed, sepals and petals are entirely absent. Still, many of these catkin-bearers possess a charm and beauty of their own, which, taken with the early, often inclement, season when they appear, make the best of them indispensable in gardens where early spring effects are desired.

As a rule it is the male or pollen-bearing catkins that are most ornamental. They are longer and more graceful than the seed-bearing ones.

POPLARS

First among Poplars to bear its flowers, and almost before winter is past, is the Aspen (_Populus tremula_). This and its weeping variety bear their catkins in February, but closely following it, and perhaps more ornamental, is the American Aspen (_P. tremuloides_). This species flowers early in March near London in mild seasons, but later further north, and when kept back by severe weather. The pendulous variety of _P. tremuloides_--known commonly as Parasol de St. Julien--is, at the flowering time, probably the most beautiful and striking of all catkin-bearing trees. This and also the type produce long, slender catkins that sway gently in the softest winds. The weeping variety, which has branches that weep naturally low, looks well by itself on a lawn. In all these Poplars the male catkins are three inches to four inches long, chiefly grey-brown in colour; the scale-like bracts, however, are suffused with a reddish shade. The weeping varieties of these two Aspens are frequently grafted on the White Poplar, which is not a suitable stock. The species to which the varieties severally belong should be used for the purpose. It would be even better if they could be got on their own roots by means of layers or cuttings, and trained up to the required height before allowing the weeping habit to develop.

There are other Poplars that bear their catkins freely, such as _P.

alba_, _nigra_, and _balsamifera_, but being of loftier habit they do not show to the same advantage as those of the Aspen group.

HAZELS

Between the middle and the end of February the flowers on the catkins of the various species of _Corylus_ begin to expand. Early as that date is, the catkins have, nevertheless, been in evidence since the previous autumn; they were, in fact, formed before the nuts fell. Being comparatively low and shrubby the different varieties of the Hazel (_Corylus Avellana_) show their catkins to best advantage, and there are few among the catkin-bearers more charming. It is not often that any but the coloured-leaved varieties find a place in the garden proper, but either in the orchard or in the woodland the soft yellow of the Hazel catkins is one of the most pleasing notes of earliest spring. The Tree Hazel (_Corylus Colurna_), a fine and interesting tree, growing thirty feet or more high, also bears its catkins in February.

WILLOWS

Of the almost innumerable species and varieties of _Salix_, it is only a few that need be mentioned here for their beauty when in flower. So far as I have been able to judge, the most ornamental of the Willows in catkin time is _Salix smithiana_, known also as _S. mollissima_. This tree flowers about mid-March, producing its shortish, thick male catkins in very great abundance; the numerous exposed anthers give a soft but glowing yellow tone to the tree, and ent.i.tle it to rank as one of the most ornamental of early-flowering trees. The pendulous variety of _Salix Capraea_ is known as the Kilmarnock Willow. Although of weeping habit it is somewhat stiff in character; but towards the end of March and later it is exceedingly pretty loaded with its grey catkins. The flowers of the typical _S. Capraea_ (the Goat Willow) are commonly known in many country places as Palm, and are used for decorating churches on Palm Sunday. The slender, coloured twigs of the Purple Willow (_Salix purpurea_) bear red or purplish-tinted catkins in early April. _Salix stipularis_ may also be mentioned for its beauty when in flower.

ALDERS

With the exception of a few species, such as _Alnus nitida_ and _A.

maritima_, which flower in September and October, all the Alders develop their blossoms in February and March. The common Alder (_A. glutinosa_) and its varieties are perhaps as ornamental as any at that time. Like the Willows, they look best and grow best in a.s.sociation with water. In such a position an Alder at that time, leafless, but laden with its slender, greenish-yellow catkins, is a beautiful object, and characteristic, too, of our English landscape. Other species possessing a similar quiet beauty are _Alnus incana_, _A. viridis_, _A. oregona_, and especially _A. cordifolia_ with its green and yellow catkins.

j.a.pANESE WALNUTS

_Juglans sieboldiana_ and its close allies, _J. mandschurica_ and _J.

cordiformis_, do not flower till May, but bear at that time very remarkable male catkins. I have measured them over one foot long, and hanging as they do in goodly number from the branches, perfectly straight and cylindrical, they have a very striking appearance, although green. All three species are alike in their catkins, but differ in the shape of the nuts. They are noteworthy, too, for the imposing character of their foliage. The leaves are pinnate, and on young trees grown in good soil are frequently three feet long. They certainly deserve the notice of planters.

GARRYA ELLIPTICA

From all the catkin-bearers. .h.i.therto mentioned, this differs in being evergreen. It is also far removed from them in relations.h.i.+p, and is closely allied to the Cornels. At the same time the catkins in external characteristics are very similar. Not only the catkins but the plants themselves are unis.e.xual, and, as is usual with the catkin-bearers, it is the male that is most ornamental. These catkins are from four inches to eight inches long, and I have heard of (but not seen) them as much as one foot in length. The time at which the flowers expand depends, as with all the early catkin-bearers, on the mildness of the season. This year on a wall the catkins have been in beauty ever since the first week of January. They are very attractive in their grace and quiet beauty.

Chiefly of soft grey and green colours, the bracts are, however, suffused with a warmer reddish tint. In the neighbourhood of London Garrya elliptica is quite hardy in ordinarily sheltered positions, but does not flower so freely as against a south wall. As it is of Californian origin this is not surprising. This shrub resents disturbance at the root, and in transplanting great care is necessary.

There are other species of Garrya in cultivation, but they are more suitable to the south-western counties than to the average climate of Britain.

To the catkin-bearing family belong several other well-known trees, such as the Birches, Hornbeams, and Sweet Chestnut; but flowering later in the year their beauty is apt to pa.s.s without notice in the great flush of bloom that comes in with April. The beautifully fragrant Sweet Gale must not be pa.s.sed without mention. Its reddish brown catkins are formed before autumn, and expand on the still leafless twigs in spring.

CHAPTER X

AUTUMN COLOURS

There is a mystery about the autumn colouring of the foliage of our many beautiful hardy trees and shrubs in this country, and we have never yet ascertained with any degree of exactness the conditions that produce the richest and brightest tints. Probably the conditions most favourable generally are provided by a good growing season--that is, a warm, moist summer--followed by a dry, sunny autumn. But it frequently happens after what one would regard as favourable seasons, that species which are usually quite trustworthy in this matter fail to colour well. Probably one set of conditions does not suit all trees and shrubs in this respect. To produce the colouration of the leaf just before it falls certain subtle chemical changes in its composition take place. And to bring about these changes certain conditions in regard to sunlight, temperature, and moisture are necessary. But in a climate such as that of Britain, where the seasons are never alike two years together, we can never hope to obtain the same regularity of autumnal colouring that characterises the vegetation, for instance, of the Eastern United States. Still, when all is said, we possess in our gardens a large number of trees and shrubs and climbers that are delightful in their autumnal livery of crimson, purple, scarlet, or gold. It is curious that every season we may notice species not usually conspicuous for their autumn tints beautifully coloured.

An over-vigorous, sappy growth, often the result of a wet, warm autumn or too rich a soil, is certainly detrimental to autumn colouring. _Rhus cotinoides_, an American Sumach, worth growing for the beauty of its colours in autumn, is one of the most unfailing in this matter. This is perhaps one of the loveliest of all autumn-tinted shrubs, and should be more planted. But young plants, put out in well-trenched, heavily-manured soil, will often fail to colour at all till they get older and less vigorous. The most beautifully coloured examples of this Sumach that we have seen grow in rather light sandy soil. We have frequently noticed, too, that various species of Vine (_Vitis_) when starved in pots will colour exquisitely, whilst others, planted out in the ordinary way, completely fail. We believe, therefore, when planting with a view to the production of autumnal colour, any great enrichment of the soil is neither necessary nor advisable, provided it is of moderate quality to start with.

In the following notes, brief mention is made of some of the best trees, shrubs, and climbers that colour in autumn:--

TREES

First among these are the American Red Oaks. Undoubtedly the best of these is a variety of _Quercus coccinea_ known as _splendens_ and _grayana_. This not only turns to a fine scarlet crimson, but it retains its foliage for some weeks after the colour has been acquired--sometimes almost up to Christmas. Other good Oaks, not so certain, however, as the preceding, are _Quercus marylandica_ (or _nigra_), _Q. heterophylla_, _Q. imbricaria_, and _Q. pal.u.s.tris_, all of which turn red. The Tupelo tree (_Nyssa sylvatica_) turns a fine burnished bronzy red. A tree remarkable for the size of its leaves, and especially for the rich golden yellow they put on in autumn, is _Carya tomentosa_, but, like most of the Hickories, it is scarcely known in gardens. _Carya sulcata_ is somewhat similar. The Common Elm is usually very beautiful in the soft yellow tints of its leaves in autumn, but another Elm of more distinct aspect is _Ulmus pumila_, a low tree whose small leaves are retained till late in the year, and turn golden yellow before they fall.

_Liquidambar styraciflua_ has long been valued for its fading foliage of purple red, but not so well known is the lovely yellow of the Fern-like foliage of the Honey Locust (_Gleditschia triacanthos_). The Tulip tree (_Liriodendron_), the Nettle trees (_Celtis_), the _Zelkowas_, and several of the Birches turn yellow, one of the best of the Birches being _Betula corylifolia_, which turns a rich orange yellow.

Among commoner trees the yellow of the Horse Chestnut, the lovely crimson of the Wild Cherry, the golden shades of the Black and Lombardy Poplars, add much to the beauty of every autumn. Several of the Maples are noteworthy in this respect, more especially the numerous varieties of j.a.panese Maples (_Acer palmatum_ and _A. j.a.ponic.u.m_), these, as well as the Mandshurian _Acer Ginnala_, turning to various shades of red. The Common Sycamore and Norway Maple change to yellow, but Schwedler's variety of the latter becomes red. Other trees that deserve mention are _Amelanchier canadensis_, whose foliage changes to lovely crimson shades in autumn; _Koelreuteria j.a.ponica_, soft yellow; _Pyrus torminalis_, bronzy red; _Ginkgo biloba_, pale gold; _Cladrastis tinctoria_, yellow; _Parrotia persica_ and _Hamamelis_, bronzy red and yellow. The Common Beech is nearly always beautiful, changing first to yellow, then to warm brown tints. _Clerodendron trichotomum_ is a small growing tree that should have a place wherever beautiful autumn foliage is desired. Among Conifers the yellow-leaved variety (_aurea_) of the Scotch Pine is remarkable in retaining its colour during the winter months only, becoming green in spring and summer. _Retinospora squarrosa_ and _Cryptomeria elegans_ turn bronzy red in winter. The warm red-brown tints of the deciduous Cypress are charming.

SHRUBS

The Sumachs (_Rhus_) furnish some of the most striking of autumn-colouring shrubs; the best of them, _R. cotinoides_, has been already described; other fine species are _R. typhina_, _R. glabra_ (with the cut-leaved variety _laciniata_), and _R. Toxicodendron_, all of which turn red. The Venetian Sumach, _R. Cotinus_, becomes yellow.

_Berberis Thunbergi_, which dies off a rich scarlet, is so beautiful in autumn that on some estates it has been planted in great quant.i.ty, not only for cover, but so that sportsmen may enjoy its colour during the shooting season. _B. concinna_ is another charming autumn-coloured leaved shrub of dwarf growth. _Gaultheria proc.u.mbens_ (Partridge Berry) is too valuable to pa.s.s unnoticed. In winter its leaves are stained with crimson. The leaves of _Cotoneaster horizontalis_ turn from green to rich shades of chocolate or crimson. The shrub is of spreading growth.

Its evergreen ally, _B. Aquifolium_, turns a glowing red or purple after the first frosts. The Ghent Azaleas almost always colour richly, either deep glowing crimson, bronzy red, or gold; and of other ericaceous plants the warm tints of _Pieris mariana_ and the rich crimson of the _Enkianthus_ should be mentioned. The taller American _Vacciniums_ (_corymbosum_ and its various forms) are always lovely. Our native Guelder Rose (_Viburnum Opulus_) becomes crimson in autumn, whilst the Common Hazel and _Rhamnus Frangula_ often produce fine effects in yellow. The feathery foliage of _Spiraea Thunbergi_ is singularly beautiful when it changes from its natural pale green to crimson; and _S. prunifolia fl. pl._ is perhaps more distinct than the species, and two other j.a.panese shrubs (both, unfortunately, very rare) are remarkable for their autumnal beauty. These are _Disanthus cercidifolia_, an ally of the Witch Hazels, lovely claret colour, and _Viburnum alnifolium_, crimson.

Other noteworthy shrubs are _Fothergilla alnifolia_, rich red; _Euonymus alatus_, crimson; _Deutzia crenata_, yellow; and _Pyrus arbutifolia_, red. The common Brambles of our woods should not be pa.s.sed over without mention; they turn a rich glowing red, and for their autumnal beauty alone may be used as undergrowth in wilder parts of the garden and woodland.

CLIMBERS

First among these, of course, is Veitch's Ampelopsis, the finest of all deciduous climbers for walls, being self-supporting and changing to crimson in autumn. _Vitis Coignetiae_ is one of the n.o.blest of all Vines, and turns crimson also. Other Vines useful in this respect are the Teinturier Vine, purple; _V. Romaneti_, red; and the Virginian Creeper, especially that variety known as _muralis_ or _Engelmannii_, which clings to walls or tree trunks without any artificial support, and acquires beautiful red shades in autumn. Among Honeysuckles, _Lonicera j.a.ponica var. flexuosa_ is noteworthy for the fine red purple of its decaying leaves. Those of _Akebia quinata_ change colour in autumn and a.s.sume shades of brownish purple, sometimes touched with maroon. Then there is _Actinidia Kolomikta_, an Asiatic species with showy yellow-coloured leaves in autumn. Of the Ivies _Hedera Helix atropurpurea_ is much the best. It has medium-sized leaves which are rich green during the growing season, but change in winter to purple and maroon.

CHAPTER XI

TREES AND SHRUBS WITH FINE FRUITS

The most important of all the groups of trees and shrubs, for their fruit, is the one comprising the hardy species of the Rose order. This includes, of course, besides the Roses, such trees and shrubs as the Thorns, Crabs, and Cotoneasters. Among the Thorns (Crataegus) are many very handsome sorts giving variety in size and colour of the fruits. It is unfortunate that many of them fall early and get spoilt by birds. At the same time birds add so greatly to the delight of the garden that we may well overlook their depredations. By many, indeed, these fruiting trees will be considered worth growing for the encouragement they give to bird-life. It may be well to remind planters that a considerable number of these fruiting trees and shrubs bear male flowers on one plant, female on another. People are often at a loss to understand why their Sea Buckthorns or Aucubas or Skimmias do not fruit, when the simple reason is that the plants are all male (or pollen-bearing), or that the female ones have no males to fertilise them. As a general rule, if these shrubs are grouped, one male to eight or ten females is a proper proportion. As plants raised from seeds come in about equal proportions of both s.e.xes, it is necessary to select the females and keep just sufficient males to pollenise them, in order that the full beauty of the species as a fruit-bearer may be obtained. With Skimmias and Aucubas the proper proportions can be obtained by means of cuttings.

The following hardy trees and shrubs are the most conspicuous for the beauty of their fruits:--

ARBUTUS UNEDO.--A native of Western Ireland, has strawberry-like fruits of a bright-scarlet colour.

AILANTUS GLANDULOSA, a fine tree over 50 feet high, is very beautiful when covered with its red and yellow-winged fruits; there are male and female plants.

AUCUBAS, grown at first for their ornamental foliage merely, have latterly come into prominence as fruit-bearers; the female plants bear cl.u.s.ters of bright-red berries which remain long on the branches and are very attractive in winter.

BERBERIS.--The fruits of the Berberries are mostly covered with a plum-coloured bloom as in _B. Aquifolium_ and _B. Darwinii_, but none of them is handsomer than our native _B. vulgaris_ and its varieties. These have pendent racemes of fruits, varying in colour from the typical orange scarlet to white, purple, and black. _B. Thunbergi_ coral-red, very beautiful.

CRATaeGUS.--The finest of all the Thorns is _C. Pyracantha_, well named by the French "Buisson ardent." This shrub or small tree is valuable as a graceful evergreen, and when clothed (as it nearly always is in autumn) with its brilliant cl.u.s.ters of orange-red haws, it is one of the most beautiful objects in the garden. It is quite hardy in the open, but bears fruits more abundantly when planted against a wall. In that position also it is more easily protected from birds, which soon destroy the beauty of plants in the open. The variety _Laelandi_ is distinct from the type, but hardier, and bears bright berries in abundance. The c.o.c.kspur Thorn (_C. Crus-Galli_) has several varieties, all producing pendent cl.u.s.ters of scarlet haws. The varieties like _pyracanthifolia_, with narrow leaves and flat-topped habit, are the best in this respect; they retain the fruits well into the winter, and are not eaten by birds so freely as many are. The haws of _C. cordata_, the Was.h.i.+ngton Thorn, are small, but a brilliant orange. _C. punctata_, _C. Azarolus_, and _C.