This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Within the last few years, and especially during the last decade, a great increase has been made in the number of cultivated plants with variegated or coloured foliage, especially in hardy trees and shrubs. Whilst many of them are inferior in point of beauty to the normal green-leaved varieties, there are a few really effective and desirable, but they should always be sparingly planted.
Trees Having Their Foliage Variegated With Yellow And Green. Sweet Chestnut (Castanea vescafoliis aureo-marginatis), Catalpa bignonioides aurea, Tulip-tree (Liriodendron tulipifera medio-picta), Common Beech (Fagus sylvatica aureo-variegatis), Elm (Ulmus campestris aurea), Sycamore (Acer Pseudo-platanus variegatus), Ash (Fraxinus excelsior aurea), and Elaeagnus Japonicus aureo-marginatis.
Trees Having Their Foliage Variegated With White And Green. Turkey Oak (Quercus Cerris variegata), Beech (Fagus sylvatica foliis argenteo-variegatis), Elm (Ulinus campestris elegantissima), Elseagnus Japonicus albo-variegatus, Negundo fraxinifolia variegata.
Trees With Coloured Foliage. The most striking of this limited group is the Purple Beech (Fagus sylvatica purpurea). The Copper Beech (F. s. cuprea) has dull reddish-brown leaves, and is not nearly so handsome. Another very handsome tree is the Scarlet Oak (Quercus coccinea), whose ample foliage changes to a brilliant scarlet hue towards autumn. Several other trees might be enumerated as worthy of consideration in planting, on account of the colour of their foliage. The Purple-leaved Sycamore, the Purple-leaved Elm, and the Abele (Populus alba), whose foliage is snowy white beneath, and Elae-agnus argenteus, with silvery glistening scales, are examples.
Trees With Brightly Coloured Bark On The Young Branches. The Gold-barked Ash and the scarlet and yellow twigged varieties of the Lime are very distinct and beautiful, more especially the Scarlet-twigged Lime.
Trees Ivith Cut Or Dissected Foliage. There is scarcely a genus, or even a species, of cultivated trees that has not produced abnormal variations of foliage, from simple to deeply divided or cut. Some of these aberrations are very ornamental, whilst others can only be described as ugly monstrosities. Very handsome cut-leaved varieties of Beech, Alder, Elm, Lime, Horse-Chestnut, Sweet Chestnut, and Oak, are described or mentioned in the descriptive portion of this work. There are three or four species of trees which deserve special notice on account of the great number and diversity of the varieties they have produced, viz., Ulmus campestris, U. montana, Robinia Pseudacacia, and the elegant Japanese Acer poly-morphum. The varieties of these trees may be counted by scores, or even hundreds in the case of the Robinia. A selection of the most distinct and ornamental is given under the respective genera.
Weeping Trees. Under this head we include only those forms in which the main branches as well as the ultimate branchlets are pendulous. Until quite recently the Weeping A;h and Weeping Willow were the only trees of this class commonly seen. Now, however, the number in cultivation has increased from units to tens. But many of them, like the variegated and cut-leaved varieties, are mere degradations of the parent forms. Amongst the more robust weeping- trees with ample shady foliage, are the Purple and Green-leaved Beech, the variety pendula of Ulmus montana, and the Weeping-Aspen (Populus tremula pendula). Sophora Japonica pendula is a very beautiful example of this peculiarity of habit. The Kilmarnock Weeping Willow (Salix Oaprea pendula) is the ordinary broad-leaved form; and several others, as well as Weeping Ash-trees, will be found described in the first part of this work. More or less pendulous varieties of the Oak, Birch, Almond, Laburnum, Thorn, Poplar, and Mountain Ash are grown, but they do not possess the same title to the appellation as those above mentioned. Besides the foregoing, there is a host of weeping forms of smaller slender shrubby plants, such as the Privet, Broom, small forms of Elm, Prunus, etc. These are grafted or budded on stems of common varieties, and form very pretty objects planted out singly or interspersed with shrubs.
Frutescent. The hardy species of woody plants coming under this denomination are even more numerous than in the first division, and offer greater variety in habit, foliage, and flowers. It should be borne in mind that many plants which never or seldom exceed the shrubby state in our climate become large trees in their native countries. And consequently the term shrub will be understood as of relative or comparative application, and as sometimes indicating the. young state of a tree. For example, in sheltered or otherwise favourable localities, the following, amongst others, attain the dimensions of small trees; Rhododendrons, Sweet Bay, Arbutus, Portugal Laurels, Arbor-Vitses, Hollies, Junipers, and Tree-Box. But as all of these in the ordinary way are shrubby, we include them here. Shrubs may be conveniently divided into two groups: Erect, and Climbing or Trailing. In each of these groups we may follow the same classification as that adopted for the trees. The term erect applies to all those shrubs that require no support to keep their branches off the ground. Thus we have : a. Evergreen erect Shrubs. - Firstly, we have shrubs with ornamental foliage and inconspicuous flowers; and here again the Conifers afford an extensive choice. The compact forms of many of the varieties of Thuja occidentalis, Biota orientalis, Taxus, Buxus, pigmy Pines and Firs, Junipers, Retinosporas, Ligustrum coriaceum, etc., are very interesting, and suitable for small gardens, single specimens on lawns, and the foreground of shrubberies. A little larger in stature and adapted for second lines and clumps are the Phillyreas, Rhamnus Alater-nus, Aucubas, the varieties of the Common Laurel, Juniperus Chinensis, J. communis varieties, Biota orientalis Japonica,
B. 0. glauca, B. o. pendula, Taxus baccata varieties, Hollies in variety, Buxus sempervirens varieties, etc.; and, in favourable localities, Euonymus Japonicus varieties, Photinia serrulata and arbutifolia, Pittosporum undulatum, Osmanthus, Japanese Hollies, tender Cypresses, Libocedrus Chiliensis, etc. In this class there are many species or varieties remarkable for their compact or formal habit. These are chiefly employed for planting in geometrical gardens as single specimens. They include the Golden Cypress, Irish Yew, Retinospora erieoides, Abies excelsa, pygmsea, and Clanbrasiliana, and many other dwarf forms of Biota, Thuja, and other Conifers, which are mentioned under their respective genera. Hollies, too, and Portugal Laurels, Sweet Bays, common Yews, and Phillyreas may be pruned into shape for the same purposes. Amongst the best of the variegated evergreen shrubs with inconspicuous flowers are: Aucubas, Hollies, Euonymus, and Box in variety, Yews, Arbor-Vitses, Osmanthus, Thujopsis, and Retinospora. Evergreen shrubs of a larger size, some of which eventually become arborescent, are: Portugal Laurels, common Laurel, Sweet Bay, Arbutus, many Junipers, Cypresses, Arbor-Vitaes, common Yew, Evergreen Oak, Abies, and Picea.
We now come to the Erect Evergreen Flowering Shrubs. In this group, although we have considerable variety, there is little difficulty in making a choice. The greater part of them are known as American plants, and grow by preference in vegetable mould or peat. But some of them, as Rhododendron Ponticum, will flourish in a rich loam. Amongst the larger-growing species we have the Portugal and Common Laurels, Laurestine, Magnolia glauca, Rhododendron Ponticum, and gradually smaller species of Berberis, Rhododendron, Grarrya,' Gaultheria, Ceanothus, Andromeda, Ligustrum, Ledum, Kal-mia, Daphne, and Erica. A selection of the best would include the following: Laurestine, Berberis Darwinii, B. steno-phylla, B. aquifolia, B. Bealii, Magnolia glauca, varieties of Rhododendron Ponticum, Rh. Catawbiense, and Rh. maximum, Kalmia latifolia and K. glauca, Daphne Cneorum, Ledum palustre, Erica carnea, Yucca gloriosa, Ceanothus azureus and
C. Veitchianus, and Andromeda and Gaultheria in Variety.