This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
We are in the habit of comparing, rather unfavourably, our hardy plants with our indoor exotics, looking upon the former as coarser than the latter, and less attractive generally; but the comparison is not a fair one. No doubt a plant grown out of doors, exposed to all weathers, looks a little less delicate than one grown under glass and by the aid of artificial heat, just as fruit under glass takes on a more delicate bloom and finish; and in comparing the flowers of the border with those of the hothouse, this should be remembered. It should also be borne in mind that many of our hardy plants, in fact the most of them, are also exotics, existing under, to them, unfavourable circumstances in this country, although succeeding well enough for ordinary decorative purposes. Take the common Geranium, for example. In the mass out of doors it does show well enough; but do the individual flowers equal those grown under glass in size and lustre 1 No : and it is the same with all hardy plants, or nearly all; and there are many that are never seen in perfection except when forced, of which the common Spiraea japonica and the Dielytra spectabilis are good examples. Neither are like the same plants when forced, or even just protected from the weather.
The plant is larger, the leaves of a more delicate hue and more perfect, and the flowers altogether superior. Before the Spiraea began to be forced, no one had any idea what a grand thing it was, and it required to be seen well grown and flowered before gardeners would believe in it. We remember it being tried for the first time many years ago in a garden in Scotland, on the recommendation of a party who had seen it in fine condition; but, as the plants forced had not been properly prepared, the result was disappointing, and the pot-culture of the plant was discontinued at the time. To see the Spiraea in perfection as well as in quantity, one must visit Covent Garden on a morning, or the window-boxes in front of the mansions of the West End, where plants in small pots, bearing numerous feathery spikes of flower of large size, attest the beauty of the plant under protection.
Practically speaking, some one may perhaps ask, What inference is to be drawn from these facts; or if it be proposed to transfer our hardy plants from the garden-border to the hothouse, in order to grow them to perfection? to which the answer is No, of course; but it is undoubtedly practicable, as well as highly desirable, to cultivate hardy plants under glass in certain cases more than has yet been done. There are numbers of people possessing, perhaps, one or two glass-houses filled with the usual assortment of indoor plants, that would have far better success and satisfaction with a collection of hardy plants, that would cost much less to begin with, and be far more easily grown and flowered. Such thoughts as these have forced themselves upon visitors to the spring and early summer shows on many occasions within the last few years, since collections of hardy plants have grown to be a feature of exhibitions. These collections, as can be seen at a glance, have not been grown out of doors, but in cool frames or houses for the occasion, and the display is proportionately fine.
At some of the late exhibitions the show of hardy plants was second to none, not even to the Orchids, which beat them in the unique character and colouring of their individual flowers, perhaps, but not in variety and general effect - did not equal them in the latter respect, indeed. The display was rich in the extreme, as the plants were well grown and flowered, and tastefully arranged, but without any set-off except their own foliage. There were brilliantly coloured Phloxes, Primulas, Saxifragas, red, white, and blue Lupins - the latter grand plants in small pots, foliage and flowers perfect - Pyrethrums, double and single, some of the latter very conspicuous by their broad star-like flowers of intense crimson colour and many other shades - Campanulas, Spiraeas, Potentillas.Aquilegias, Wallflowers, Iris, Liliums, Narcissus, Funkias, and many other things, presenting nearly every bright or pleasant shade, and all varieties of form. Such collections give one an excellent idea how rich and effective a flower-border of such plants may be made by a judicious selection of such subjects. The varieties of hardy plants are innumerable almost, but those which have only a botanical interest are not wanted in beds of pretty flowers.
The botanical garden which displays the original types of the different species looks very different from a collection of the same species represented by its cultivated varieties, as a rule; for there are, of course, numbers of original forms that are also attractive and showy. The cultivated and improved hardy border-flowers stand in nearly the same relation to their primogenitors that the cultivated Carrot or Cauliflower does to the wild type of their class.
All hardy plants, or nearly all, may be cultivated with great ease in pots either in the border or in the frame or the greenhouse, and the least assistance in the way of protection brings them into flower long before they would flower in the open border, - hence they form an excellent adjunct for conservatory decoration. Iris reticulata, for example, displays its beautiful flowers in mid-winter or earlier in a cold pit; and numbers of other varieties come in proportionately early. The mere protection of a hand-light or a cloche will cause many spring flowers to bloom long before their time; and if they are in pots, they may be lifted and placed in either the greenhouse or the window. In short, spring flowers bloom, when protected, in winter; summer flowers in spring; and autumn ones in summer. Without exception, one of the finest window-plants we ever saw was an Anemone japonica alba, - a large plant that stood on a stand by itself in the bay-window of a drawing-room, where it had grown, and flowered in July. The foliage was as large and green as that of the Vine indoors, and quite spread over and hid the pot, and the flowers were larger and purer than they are even seen outdoors.
The plant stood in the window of a mansion on the promenade of a seaside town, and numbers of people stopped to look and admire the fine specimen, wondering at the same time what it was, and many going away no doubt in the belief that it was some rare and little-known plant. It is noticeable now, however, that hardy plants in pots are a greater feature of the market-growers' stalls than they used to be. Anemones and Primroses are common, and the pretty Iberis corifolia is becoming a favourite, being of a compact habit of growth, and a great improvement on the old variety.