Trees and Shrubs for English Gardens Part 14

The practice that is frequently adopted of forming a pinetum and bringing together the members of this family in one part of the grounds is a very good one. It is far better than sprinkling them indiscriminately over the whole garden. At the same time, where sufficient s.p.a.ce is not available for the formation of a pinetum they may be used in their proper proportion with other evergreens in various parts of the garden. Single specimens on lawns of Abies, Picea, and of many other genera are always effective, and nothing in the whole range of native or foreign trees is more stately and picturesque than the Cedar of Lebanon. How much do we of the present day owe to those who a century or more ago planted this tree so abundantly in this country!

Before planting Conifers largely in any garden where they are to be grown for their purely ornamental qualities, a study should be made of the species planted in other gardens where the conditions as to soil, moisture, and alt.i.tude are similar. On the peaty formations in Surrey and Hamps.h.i.+re where Rhododendrons succeed so well, many Conifers thrive exceedingly well also. The Common Spruce and its allies are nearly all failures on light dry soil, especially where the subsoil is gravel. In places, however, where the Spruces fail, the Common Larch and the Lawson Cypress succeed well. In chalk districts many Conifers refuse to grow, but the following are among those that thrive: _Abies magnifica_, _A.

n.o.bilis_, _A. nordmanniana_, and _A. Pinsapo_, the Cedars, _Cupressus lawsoniana_, _C. macrocarpa_, and _C. nootkatensis_, the Maidenhair tree, the Junipers, the Thuyas, the Yews, and the following Pines: _Pinus Laricio_ and _P. austriaca_, the Scotch Pine, _P. excelsa_, and _P. Pinaster_. Most of the Pines, too, are happy on gravelly or stony ground.

None of the Silver Firs (_Abies_) or Spruces (_Picea_) are good trees for planting at the seaside, unless there is sufficient shelter to break the force of the wind, and even then there are very few that will succeed. The species most suitable for planting where there is a thick outer belt are _Abies n.o.bilis_, _A. concolor_, _A. nordmanniana_, and _A. pectinata_, the Common Silver Fir. Of the Spruces, _Picea nigra_ and _P. alba_, the North American Spruces, succeed better than the Norway Spruce, _P. excelsa_, but these, like the Silver Firs, must have the shelter of a good wind break; _Picea pungens_, _P. pungens glauca_, and _P. Engelmanni_ will not succeed in exposed places, even in inland localities, and fail entirely by the sea. There is a difference of opinion about _Engelmanni_. In some places it seems to stand winds well.

The Conifers that will thrive by the sea are very few, and probably not more than half-a-dozen kinds can be trusted. The finest of all is undoubtedly _Pinus Pinaster_, which is essentially a sea-coast Pine, revelling in storms and sprays. For warmer parts, is the Aleppo Pine (_P. halepensis_), but is only for southern and warm coasts. _P.

insignis_ is somewhat tender, but stands the sea gales fairly well, and _P. austriaca_, and its relative, _P. Laricio_, are both excellent, specially for making the first barrier against the winds. The hardy Scotch Pine (_P. sylvestris_), if planted in large ma.s.ses, grows well, but does not luxuriate close to the sea, and is especially liable to be browned in foliage by the salt spray.

Besides the Pines, one of the finest of Conifers is the Monterey Cypress (_Cupressus macrocarpa_), which is hardy everywhere on the coast in these islands; it grows finer than it does in its home on the Pacific coast. It makes a fine front barrier against the wind, especially when mixed with the foregoing Pines. The variety _C. lambertiana_ is also excellent. There are two other Conifers which, though not much planted by the sea-coast, will, we believe, prove reliable; these are _Cedrus atlantica_ and _Thuya gigantea_ (sometimes called _T. Lobbii_). A third Conifer that we have seen doing well by the sea is _Abies Pinsapo_, but it must have a temporary shelter in its small state. This subject of seaside planting--the most difficult in a tree planter's practice--is an important one, and it is only possible to treat the matter generally.

The Conifer family is especially noteworthy for the way many of its species vary. Not only is this propensity evidenced in such characters as the colour of the leaf and the differences in habit; it shows itself more remarkably sometimes in the form and texture of the leaf and mode of branching. So great is the difference between some forms of certain species of Conifers that they have been placed in different genera. What are generally known as Retinosporas, for instance, are really nothing more than forms, "states" the botanists term them, a.s.sumed by various species of Thuya and Cupressus. Strictly speaking, _Retinospora_ has no separate existence as a genus. This, however, is a botanical phase of the matter. Horticulturally we are more concerned with such variations as adapt the plants to various garden purposes. Many quaint and dainty forms of large trees are very suitable for the rock-garden in a.s.sociation with other alpine plants. The Common Spruce, for instance, has given birth to many pigmy forms. The Yew, the Scotch Pine, and various others have "sported" in a similar way. But no hardy tree varies so much, perhaps, as the Lawson Cypress when raised from seed. The species has a.s.sumed almost every shade of colour that Conifers do a.s.sume, and every form of growth. Beautiful golden, variegated, pendulous, and erect varieties have been raised, and not only from the Lawson Cypress, but from many other Conifers also. The Golden Yews, the yellow form of the Monterey Cypress, and the golden variety of the Scotch Pine, may be recommended to those who require this colour, although in the Pine it only shows itself in winter. The blue-white or glaucous hue that is more or less present in most Conifers, shows itself most conspicuously in the Blue Spruce (_Picea pungens glauca_), in _Cedrus atlantica glauca_, in the new Cork Fir from Arizona (_Abies lasiocarpa var. arizonica_), and in _Abies concolor violacea_.

THE PROPAGATION OF CONIFERS

Many mistakes have been made in propagating the Coniferae, and to make matters still worse, the old erroneous doctrines are still preached and practised. The unpopularity of certain species of Abies, Picea, and Pinus is due to a great extent to the practice of grafting them on unsuitable stocks. For instance, the species of Abies are worked on _A.

pectinata_, of Picea on _P. excelsa_, and of Pinus on _P. sylvestris_ or _P. Laricio_. The varieties of _P. excelsa_ are worked on that species.

_P. excelsa_ is _not_ used for the other forms of spruce Firs to any great extent. In addition to this, such methods and stocks are still spoken of as the correct ones to use; though, to take one genus alone, what kind of a specimen _Abies bracteata_, _A. n.o.bilis_, or _A.

concolor_ would make in twenty years' time if worked on _A. pectinata_ we should not like to say--certainly very poor, even if they lived, which is doubtful. These are nearly always raised from imported seeds.

It may be laid down as a law that _species_ of Coniferae should never be grafted but raised from seed, which can always be obtained through English firms. With varietal forms of Coniferae that will not come true from seed or that cannot be struck as cuttings, grafting must be resorted to, and if young plants of the type species are used as stocks the results will be fairly satisfactory. In the case of some of the more highly variegated Cupressus, &c., grafting is really the best method of propagation, as these forms are mostly of weak const.i.tution and are not satisfactory from cuttings. In the following list the best methods of propagation are given with each genus, together with special mention of those forms which are of indifferent growth though not difficult to propagate:--

JUNIPERUS.--The Junipers should be raised from seeds, though some of them do fairly well if propagated by cuttings. The green and glaucous varieties of _J. chinensis_, _J. excelsa_, _J. virginiana_, and _J.

communis_ root easily from cuttings, or can be layered with success. The variegated forms are best grafted on stocks of the species they belong to, and _J. Sabina_ (the Savin) and its varieties are easily raised from cuttings or layers, the latter being a very easy way of propagating them.

CUPRESSUS.--This genus is divided into two sections, viz., the true Cypresses, represented by _C. macrocarpa_, _C. sempervirens_, &c., and Chamaecyparis, of which _Cupressus lawsoniana_ is the best known species.

With the former section seeds are the best means of reproducing the species, while the few varieties should be grafted on stocks of the parent species. The handsome _C. macrocarpa var. lutea_ especially should be worked on the type, as it is practically a failure from cuttings, and if grafted on _C. lawsoniana_, as is sometimes done, it makes a short, stumpy bush instead of a typically tall columnar tree. In the Chamaecyparis section _Cupressus lawsoniana_, _C. nootkatensis_, _C.

obtusa_, _C. pisifera_, and _C. thyoides_ are the only species, though there are a host of varieties attached to them, the forms of the three latter species, in fact, including all the various plants more commonly known under the generic t.i.tle of Retinospora. The species should be raised from seed, which is easily obtainable and germinates readily, or in default they will root from cuttings. The varieties, with a few exceptions, are quickly propagated by cuttings, those that require to be grafted being _C. lawsoniana var. lutea_, the variegated forms of _C.

nootkatensis_, and _C. obtusa vars. nana_, _nana aurea_, and _filifera aurea_. The forms of _C. thyoides_ also do well when raised from layers.

We must not omit also such varieties of _C. lawsoniana_ as _Fraseri_, _Allumi_, and one known in nurseries as Milford Blue Jacket.

THUYA.--These are propagated in much the same way as the Cupressus, viz., the species by seeds, and the varieties by cuttings or by grafting in the case of the one or two highly variegated forms. Some of the green or glaucous varieties of both Cupressus and Thuya will come fairly true from seed, from 40 per cent. to 70 per cent. being the usual quant.i.ty of seedlings true to name. Variegated forms from seed either come green or a mongrel mixture of green and variegated.

LIBOCEDRUS.--This should be raised from seed, as when grafted on _Thuya orientalis_--a too common method of propagation--it makes a miserable specimen. The middle pair of scales in the cone of Libocedrus alone contain fertile seeds. _L. doniana_ is a tender species.

SCIADOPITYS and TAXODIUM.--These can only be propagated by seeds, and the young plants should have a fairly moist position with plenty of leaf-mould or peat to grow in afterwards.

SEQUOIA.--The two species of Sequoia should be raised from seed, and the three or four varieties be grafted on the type species.

CRYPTOMERIA.--This only contains one species, viz., _C. j.a.ponica_, which can only be obtained from seed, or by cuttings; and the varieties root readily as cuttings, though one or two of the weaklier ones do better if grafted on _C. j.a.ponica_.

ARAUCARIA.--Propagate by seeds, which, though sometimes difficult to obtain, germinate freely and quickly.

TSUGA.--The Hemlock Spruces are easily and quickly obtained from seeds, and one or two will strike from cuttings; the varieties do best when grafted on the species they belong to, though _T. pattoniana var.

glauca_, more commonly known as _Abies hookeriana_, will come fairly true from seed, about 75 per cent. being the usual quant.i.ty if the seed is obtained from good plants.

PICEA.--This genus has been mentioned before as being commonly grafted on _P. excelsa_ (the Common Spruce), which is an easy way of obtaining young plants, which, however, cannot be recommended to form good specimens in after years. The species of Picea should all be raised from seed, and the many named varieties of _P. excelsa_ should be grafted on the parent species. At least one-half the plants of _P. Engelmanni var.

glauca_ and _P. pungens var. glauca_ (the Californian Blue Spruce) will be found true to name when raised from seeds, while their superiority afterwards over grafted plants is evident.

CEDRUS, LARIX, AND PSEUDOLARIX.--It should always be remembered that these three are quite distinct genera, and for purposes of propagation should never be used in conjunction with each other, the first being evergreen and the two latter deciduous. The species of all three should be raised from seed; the varieties of Cedrus should be grafted on that genus, the forms of Larix on the Larch, though the geographical forms of the Common Larch, such as _var. rossica_ and _var. sibirica_, usually come true from seed. _Larix leptolepis_ (j.a.panese Larch) is one of the most beautiful trees ever introduced from j.a.pan; it is charming both in summer and winter. _Pseudolarix Kaempferi_ (Golden Larch), the only representative of the genus, must be raised from seed; it is generally raised by grafting in February under gla.s.s on stocks of the common Larch.

ABIES.--In this genus some of the most handsome Conifers are found, and also some of the most difficult to grow. All the Abies should be propagated by seeds, but if seed of the varieties cannot be obtained then they must be grafted on the parent species.

PSEUDOTSUGA.--This genus only contains one species, viz., _P. Douglasii_ (the Douglas Fir), which is propagated readily by seed, the seedlings being of rapid growth and soon form good plants. The few varieties are grafted on the type, though the majority will come fairly true from seed, which, however, is not always to be obtained.

PINUS.--Perhaps no Conifer adds so much to the beauty of the landscape in winter as the Pine. All the species should be raised from seeds, and any green or glaucous varieties can also be propagated in the same way if seeds can be obtained. The golden, dwarf, and variegated Pines must be grafted on the species they are varieties of.

TAXACEae.--This group is usually a.s.sociated with Coniferae, from which it differs chiefly by the seed being nearly or quite enclosed in a fleshy envelope instead of in a cone, the fruit of some resembling a small Plum, but a typical fruit is seen in that of the Common Yew. The hardy genera are _Ginkgo biloba_ (the Maidenhair tree), which is propagated from seed--the plant is deciduous and slow growing; Cephalotaxus and Torreya are propagated by seeds, cuttings, or layers.

TAXUS (the Yew).--There are only three or four species of Taxus, but there are a great many varieties of the Common Yew, many being very handsome. The species are easily raised from seeds, layers, or cuttings.

The first two methods are the best, cuttings being very slow in growth, but as seed is very plentiful in most years this is the quickest and best means of propagation. Some of the varieties will come true from seed; the Irish Yew, however, must be struck from cuttings, as seedlings never come true. The more highly variegated Yews grow quickest when grafted on the Common Yew, and as they always keep good in after years this method can for once be recommended. A very good species for a lawn is _T. cuspidata_; it is strong in growth and spreading.

Propagate PRUMNOPITYS and SAXEGOTHEA by seeds, cuttings, or layers.

CONIFERS AT MURTHLY CASTLE, PERTHs.h.i.+RE

[Ill.u.s.tration: _AVENUE OF ANCIENT YEWS AT MURTHLY._]

The following account of a great Conifer garden in Scotland is important, as showing how certain of the better-known species have behaved during the last fifty years or so. It is taken from the _Garden_ of May 19, 1900:--

The second quarter of the present century saw the introduction of a large number of Conifers. .h.i.therto unknown to English gardens. Their cultivation was eagerly taken up, and especially in Scotland, a land whose general conditions seem highly favourable to a considerable number of species, much success has been attained. It may still be premature to state with any degree of a.s.surance what may be the ultimate suitability of many of these Conifers for growth in our islands. The lifetime of a tree is not comprised within its first sixty years, and such a length of time is all too short to prove the ultimate success of any new tree, though within that s.p.a.ce it may come to a magnificent size and apparent promise. Such a state is shown by the splendid Douglas Firs in the grounds of Murthly Castle, Perths.h.i.+re, where also many another exotic Conifer is grown in quant.i.ty.

These words of Sir William Thiselton-Dyer, that formed part of his opening address on the second day of the Conifer conference of the Royal Horticultural Society in 1891, may here be quoted:--

"Any one who had not travelled in Scotland could form no idea of the extent to which rare Conifers were cultivated in that country, and the splendid development which they attained. The chairman, by way of ill.u.s.trating these remarks, directed the attention of the audience to some large photographs representing specimens of Coniferae to be seen at Murthly Castle, Perths.h.i.+re, where they flourished, and where stately and magnificent examples 70 feet, 80 feet, and 100 feet high were to be met with. Such trees could only be seen in Scotland, and were the result of a peculiar a.s.sociation of physical conditions. In the south-west of England it was impossible to find a parallel, though even on the sunburnt soil of Kew good specimens of the Pines proper were occasionally to be seen. With regard to the Abies, however--that section of Conifers of which the Spruces may be taken as a type--a state of things prevailed in Scotland which could not be rivalled in England. On the other hand, the climate in the south-west of the latter country was fairly suitable for some other Conifers, and many of the fine Mexican Pines could be grown there."

Of the remarkable Douglas Fir at Dropmore, Mr. Charles Herrin on the same occasion says: "The monarch Douglas Fir, planted in 1830, has attained a height of 120 feet, girth of trunk 11 feet 9 inches, with beautiful spreading branches sweeping the ground, covering a diameter of 64 feet. The leaves are also of a glaucous hue, equalling in that respect many of the plants now sold from nurseries under the name of _Douglasi glauca_.... Many trees have since been raised from its seeds and planted out on the estate; one, planted in 1843, is now 78 feet high, with a girth of trunk of 8 feet 2 inches, spreading 39 feet in diameter at base; a perfect specimen."

By comparing the growth of the latter tree with the Murthly table, it will be seen that the trees make their growth much more rapidly in Scotland. The Murthly Conifers were all planted by Sir William and Sir Douglas Stewart. The present owner, Mr. Steuart Fothringham, who measured the trees in 1891 in antic.i.p.ation of the visit of the Scottish Arboricultural Society, on learning that we should be glad to know their increase of growth since that date, has been so good as to have the same trees measured again, the increase being shown by the subjoined table on p. 128.

Mr. Fothringham also furnishes the following remarks: "The measurements were all carefully taken by sending men or boys up the trees, not by dendrometers, and are, I believe, correct. There are something like eighty or a hundred different varieties growing at Murthly, but some of them are young and only experiments. Those measured and noted are the most striking; they are nearly all growing in large numbers. The remarks appended to the table are made by Mr. James Laurie, the gardener, who knows Conifers well. The only additional notes I have made are the following: _Picea sitchensis_ will never, in my opinion, supplant the Spruce. _Picea orientalis_ is not as free-growing as the Spruce, but quite as hardy. _Araucaria imbricata._--Many of these were damaged by severe frost. _Cedrus Deodara_ will not, in my opinion, live to great age in our climate. _Cupressus thyoides._--This particular tree was so much broken by branches blown off its neighbour that I cut it down.

_Pinus monticola_ has been attacked by a parasitic growth that is likely to destroy all the young growth and probably the trees. _Juniperus recurva_ was severely injured by the hard frost. By the hard frost I mean the winter of 1894-5. In February 1895, the thermometer was for several days below 0 Fahr., and on one night went to 11 below 0. This shows that all these trees will stand great cold at the time of year that it is likely to come, but late frosts in spring, when the sap has begun to rise, are detrimental to the young shoots of those that start their growth early in the season. There are at Murthly, besides Coniferae, fine specimens of Yews, Oaks, Beech, Spanish Chestnut, Horse Chestnut, and Sycamore."

Key: A - Height.

B - Girth at 5 feet.

C - Spread of Branches.

---------------------------------------+-------------------+-------------------- August 11, 1892. March 24, 1900.

+------+------+-----+-------+------+----- A B C A B C +------+------+-----+-------+------+----- Wellingtonia, planted 1857[a] 66.6 9.3 26 74.11 10.7 28 Picea sitchensis, planted 1845[b] 91.9 9.7 45 105.10 11.3 ...

Pinus monticola, planted 1850[c] 67 5.6 18 79.2 6.2 22 Araucaria imbricata, planted 1847[d] 42.6 4 9 51 4.8 9.8 Abies Pinsapo, planted 1847 34.8 6.6 ... 42.6 7.10 ...

,, magnifica, planted 1867 31.9 2.7 9 43.3 3.8 11 Pseudotsuga Douglasi, planted 1847[e] 86.6 8.10 24 97.4 9.10 27 Abies grandis, planted 1852 64.2 4.8 22.6 79.10 6.10 35.8 Tsuga albertiana, planted 1860 56 5.5 32 72.1 6.4 40 Abies n.o.bilis, planted 1847 75.4 6.1 ... 92.8 6.6 ...

,, nordmanniana, planted 1854 58.6 4 ... 74 4.9 ...

Tsuga hookeriana, planted 1862[f] 30 4 15 39.6 4 15.4 Cedrus Deodara, planted 1842[g] 51.3 6.8 26 61.2 7.4 36 ,, Libani[h] 65.10 11.8 ... 67 12.5 ...

Cryptomeria j.a.ponica, planted 1852 36.3 4.2 26 41.7 4.3 ...

Libocedrus decurrens[i] 34.8 3.6 10 38 4.5 14 Thuya gigantea, planted 1862 46 3.6 21 57 3.7 ...

Cupressus lawsoniana, planted 1859[j] ... ... ... 48.7 4.2 ...

Spanish Chestnut ... ... ... ... 17.10 ...

,, ,, [k] ... ... ... ... 19.2 ...

Silver Fir[l] ... ... ... 90 11.3 ...