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.
Old gardeners, and gardeners in their prime, will remember a time when greenhouse shrubs, or, as they were generally named, hard-wooded plants, were the principal, if not the sole, occupants of the greenhouse in British gardens. The various tribes and genera of New Holland and New Zealand shrubs, along with the Heaths of the Cape, the Camellia, the Azalea, and a considerable gathering of beautiful shrubs from various parts of temperate Asia, were in those days the glory of the greenhouse and conservatory, and all places that claimed to be well appointed; and in those even which had no such claim, a sprinkling of them found a place and were delighted in. A change has been gradually but surely brought about in this, as in many other matters in gardening; and now it is as rare to meet with a good collection of these old-fashioned greenhouse shrubs as it is to meet with a gardener much under forty years of age who knows or cares much about them. Heaths, Epacrises, Camellias, and Azaleas, still remain in greater or less variety and numbers about most places.
These could not be dispensed with on account of their value as winter and spring flowering plants; they were therefore adapted to meet the changing taste and growing wants of the proprietors of gardens, and have increased in variety and usefulness since the time when they alone, of the hundreds of other greenhouse shrubs then commonly cultivated, were found comparatively facile helps to gardeners in compassing the wishes of their employers.
In all changes there is something to regret and something to rejoice in. The force of this truism applies equally to changes in gardening taste as to changes in far more important affairs. I for one regret very much that the most interesting and beautiful class of plants in question are now so rare that they are only to be found in a few of the grand places sparingly, and in the botanic gardens. But I rejoice also that other beautiful plants, though more trivial objects of the gardener's art, but not therefore less useful to the attainment of the end for which he works, have sprung up into importance. No one appreciates more the improvement, both in cultivation and quality, that has been effected of late years in the China Primrose, the Chrysanthemum, Cineraria, Calceolaria, Pelargonium, and the Fuchsia, which, with the increased taste for the various bulbs adapted to forcing, and the demand for increased accommodation for bedding-plants, have been mainly instrumental in elbowing the less tractable classes of hard-wooded plants out of general cultivation. I appreciate fully all this progress, but am conservative enough to regret the loss, and long for the reinstating of many of the beautiful and interesting old-fashioned shrubs of the greenhouse in their former place and favour.
About the old-fashioned greenhouse shrubs there was a substantialness of character, with grace and variety of habit, and beauty, interest, and variety in the form and colour, which are, comparatively speaking, wanting in the few forms of plants that now occupy their place in the greenhouse for a brief season, and then are discarded for ever. When a Calceolaria or Cineraria has finished flowering, it is, so far as the purpose of decoration is concerned, used up; it may serve the purpose of reproduction afterwards, but nothing more. And so it is with most of the plants that have taken the place of the more enduring old-fashioned shrubs of the past. About these latter, interest accumulated from year to year insensibly, as it gathers round a household god. If one or other of them died, it left a blank not soon to be filled up - a circumstance not calculated to raise them in the estimation of those who delight only in the comparatively rough-and-ready courses of cultivation which perfectly succeed in bringing in relay on relay several times a-year of the useful classes of herbaceous plants alluded to, but which keenly sharpened the cultural wits, and concentrated the attention of all concerned in their cultivation in the time when hard-wooded plants were the glory and pride of a successful plant-grower.
If the respective merits of hard-wooded and herbaceous plants for the decoration of the greenhouse are fairly examined, the former are by no means eclipsed by the alleged superiority of the latter. It is true they cannot in general be forced and brought in at different seasons of the year, and this is the strongest argument against them in a general way; but it is of small force when it is remembered that in their varied ranks many species, and even families, when well selected in accordance with the end in view, may be brought together to maintain a display of flowers in the greenhouse the year round. The display may be less massive than that produced by the plants at present employed for the purpose, but it may, I think, be claimed for it that it is accompanied by an amount of variety and freshness of interest that mere massiveness fails to yield to the beholder. But in some genera of greenhouse shrubs there is no deficiency even in the quality most sought after in flowering plants at the present time.
What among the popular soft-wooded plants can equal the profusion and massiveness of the Acacia Riceana, the splendid plant of which in the corridor at Floors Gardens is worth going a long way to see? Other species of Acacias may be mentioned which are perhaps inferior to Riceana in point of grace and rich profusion of bloom, but in no degree are they inferior to the best display which can be produced by soft-wooded plants in similar colours, and of such A. Drum-mondii, grandis, and celastrifolia may be instanced as examples which by no means exhaust the list. Elegance of colour and form are special characteristics of this numerous and diverse class of plants; and it is wonderful, in these days when the efforts of gardeners are directed so strongly to the production or introduction of something new in the decorative way, that some favour has not fallen on the best at least of them. The object of this paper is not to insist on any superior fitness which they have over any other class to meet the growing demand for greater variety in flowering greenhouse plants, but to show that among hard-wooded plants as a class may be found all that is wanted to meet that demand.
A more general adoption of the old practice of growing them in collections by themselves, wherever the means admit of it being done well, would be a wholesome step; it would give young men more frequent opportunities of becoming acquainted with the plants themselves, and of learning how to cultivate them. W. S.