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.
The most commendable binary combinations are as follow, which we arrange in the order of their respective merits : a. All colours, simple and compound, with white, though the brighter and purer the colours the more pleasing the contrasts; for example, bright or deep blue with white, rose or red with white, bright yellow with white, orange with white, green with white, and violet with white.
b. The simple colours together, or with their complemen-taries, such as red and yellow, red and blue, yellow and blue, yellow and violet, orange and blue, and green and red.
Ternary combinations are far less numerous, and in most cases white is an element; often, indeed, it is repeated. The following examples will enable one to judge : White, red and green; or white, red, white and green; - blue, orange, blue and white; or white, orange, white and blue; - white, yellow, violet and white; or white, yellow, white and violet; - yellow, red, white and yellow; white, red, blue and white; or, better, white, red, white and blue; - white, orange, green and white, or better still, by interposing white between the orange and green; - white, orange, white and violet; or, still more effective, white, orange, white and violet; - white, yellow, green and white; - white, yellow, blue and white; or the same combination with the yellow and blue, separated by the white.
These examples, which we might multiply indefinitely, will suffice to make the laws clear that should be observed in this sort of combinations. In cases where the absence of desirable colours renders it necessary to associate those which are not complementary, they may be advantageously separated by white. We may add that in mixed bedding, where the colours are generally some distance apart, the foregoing laws may be more or less relaxed.
Without entering into the arrangement of large plants with ornamental foliage, and the crowd of tender species now employed in some establishments to form what are termed the Sub-tropical and Picturesque gardens, we may indicate a few of the plants that are easily obtained, and usually grown for summer bedding purposes,1 classified according to their colours. There is a vast number of varieties with flowers of innumerable shades and colours, of such genera as Pelargonium, Verbena, Dahlia, etc.; but for massing only those with distinct and decided colours are admissible.
a. (1.) Plants with Red, Scarlet, Crimson; Cinnabar, etc., Floivers. - Begonia fuchsioides, Cuphea eminens; Dahlia, many varieties, especially the dwarf and small-flowered ones; Pelargonium (Geranium) Tom Thumb, and many other varieties; Gladiolus, various; Lantana Camara varieties, Lobelia cardinalis varieties, Mimulus cardinalis varieties, Pentstemon various, Phlox Drummondii, Tropseolum (Nasturtium) various, Roses in variety (pegged down), Verbena varieties, and Zinnia. (2.) Carmine, Violet and Purple Reds, Rose, Cerise, etc. - China Asters, Balsams, Chrysanthemum roseum, Dahlias, Linum rubrum, Mimulus cardinalis, Pelargoniums, Pent-stemons, Phlox, Roses, Senecio elegans, Candytuft, Verbenas, Tropseolum (Nasturtium).
b. (1.) Plants with Yellow Flowers: Pale Orange. Canary, Lemon, etc. - Antirrhinums, Calceolarias, Dahlias, Erysimum, Eschscholtzia Californica, Bartonia aurea, Gazania splendens, Helichrysum, Waitzia, Lasthenia glabrata, Lupins, Mimulus luteus, African Marigolds, and other varieties of Tagetes, Double Common Marigold, Tropseolum, Zinnia, etc.
Agapanthus umbellatus, Ageratum varieties, Campanula various, Centaurea Cyanus, Delphinium formosum, etc., Eryngium alpinum, Gilia capitata, Heliotrope, Linum, Lobelia, Lupins, Nepeta, Plumbago Capen-sis, China Asters, Salvia patens, Viola cornuta varieties, etc.
Ageratum, Balsams, Candytuft, China Asters, Campanula (white varieties of various species), Cerastium tomentosum and Biebersteimi, Chrysanthemum roseum varieties, Dahlia, Pelargonium, Lupins, Phlox Drummondii, Roses, Spiraea Filipendula, Verbena, Zinnia, etc.
The foregoing lists might be trebled or quadrupled; but as allusion is made to these supplementary bedding-in plants in the Classification of Plants, this will be sufficient for the purpose intended.
We may add a small selection of Redding plants with coloured or variegated foliage. Those in which two or three colours are blended are well represented by the Zonal and Ivy-leaved Pelargoniums, and the varieties of Coleus Blumei, Veitchii, etc.
Foliage nearly White, or Variegated with White. - Alyssum maritimum, Arabis lucida, Centaurea Ragusina and candidis-sima, Cerastium tomentosum, etc., Senecio (Cineraria) mari-timus, Phalaris arundinacea, Mentha rotundifolia, Polemonium caeruleum, Stachys lanata, etc.
Foliage Yellow, or Variegated with Yellow. - Pelargonium several varieties, Chrysanthemum Parthenium aureum, Golden Feather.
The above enumeration provides only for the summer decoration of a parterre; but where the outlay is of secondary importance, it is usual to have two or even three sets of plants in the beds during the year, and where expense is an object we should recommend the mixed style. As soon as the weather renders it necessary to remove the summer plants, the beds may be made attractive for the late autumn and winter months by filling them up with miniature evergreen shrubs. It is preferable to have these previously established in pots, and then to plunge them into the beds with their pots. The shrubs best adapted for this purpose are those of slow growth, and those which will bear close pruning, and then with care in transplanting, the same plants would do for several seasons. There is a great choice in the Coniferse, including some of the small forms of Biota orientalis, Thuja occidentalis, Cupressus Lawsoniana, C. Nutkaensis, Retinospora spp., Irish and other Yews, etc. Of miscellaneous subjects suitable for this purpose we may name : Cotoneaster microphylla, with berries; Laurustinus, flowering bushes; green and variegated Hollies, berry-bearing, if possible; Aucubas also; several varieties of Buxus, Portugal Laurel, Erica carnea, and various Ivies. These shrubs might remain through the winter and until the middle of May, when they would be replaced by the summer plants, or they might be removed about the end of February, to make way for spring flowers. It is abundantly clear, however, that this system could only be carried out where the resources are equal to furnishing a supply of spring flowering plants in pots, already so far advanced as to make some show when turned out. In the case of bulbous-rooted plants, it might be so managed that they could be planted between the shrubs at the proper time in autumn; and where Crocuses and Snowdrops are used, there would be ample space for a bordering of them out§ide of the shrubs.