This section is from the book "Sub-Alpine Plants Or Flowers Of The Swiss Woods And Meadows", by H. Stuart Thompson. Also available from Amazon: Sub-Alpine Plants: Or, Flowers of the Swiss Woods and Meadows.
The culture of Alpine and rock plants as a hobby is increasing by leaps and bounds. We remarked a year ago that nothing was more indicative of this increasing fashion than the number of books issued in recent years on the subject, and the amount of space devoted to it in horticultural journals. Since then several more books have appeared, including a practical and prettily illustrated little volume on Rock Gardens and Alpine Plants by Mr. E. H. Jenkins, who has had much experience in the making of rockeries and the management of Alpine and other hardy plants.
In Mr. Flemwell's last volume, The Flower-fields of Alpine Switzerland, the latter portion of that beautifully illustrated work was devoted to a plea for the formation of Alpine fields in England, and some very plausible arguments were advanced for the introduction of Swiss pasture and meadow plants into grassland as an adjunct to our rock-gardens. It was also proposed to decorate with Alpine flowers not only some of our parks and public places, but it was suggested that many a wayside field, copse, bank or railway-cutting might be improved ' by taking a leaf from Nature's Alpine book.'
Theoretically such an idea is excellent, and it is true that many of the handsome sub-alpine plants of the Swiss meadows and open woods would figure largely in any such scheme; and that some of these flowers of the lower mountains have been neglected by gardeners. Some horticulturists are ready to look kindly only upon anything that will grow on a rock, and to call it 'Alpine'; and certain small Alpine meadow and pasture plants frequently planted on dry rockeries in England languish and die because they are out of their natural habitat.
For the suggestion that a small field or enclosure adjacent to a rock-garden should be converted, with skill and taste, into an Alpine pasture, we have nothing but praise; and it has already been successfully done by several gentlemen. It is only fitting that a large rock-work should, where practicable, be completed or supplemented by an 'Alp' or small field where numerous meadow and woodland plants could be established and grown to advantage. But, we say - let it stop there, and chiefly for this reason. If many foreign plants were introduced into out fields, copses, and railway-cuttings, and especially any Alpine species which do not already grow wild in England, it would soon upset the balance of distribution of our native flora, and the calculations of future generations of students in geographical botany. It must not be forgotten that the topographical distribution of the native plants even in these small islands is a subject abounding in interesting points, and the fact that it has been suggested of recent years that some of the commonest species such as the White Dead-Nettie (Lamium album), hitherto supposed to be indigenous, were introduced by the Romans or more recently, makes it all the more incumbent upon us not to ' make confusion worse confounded.' Therefore, however poor in floral wealth and colour some of our own fields and meadows may be in comparison with those of Alpine countries, let us be satisfied with our Primroses and Bluebells, our Buttercups and Daisies,and not sacrifice science to artistic effect, however tempting the experiment may be.
In regard to the making of rock-gardens, we do not propose to offer more than a few very general remarks, for, in addition to the fact that there are practical books already devoted to the subject, this is emphatically a case in which a little practice is worth much theory. Much can be learnt by observing Nature, and by noticing the way in which many plants grow upon the rocks at home, and how they adapt themselves to different local conditions. A single visit to the Alps will teach still more.
In making a rockery the chief thing to secure is thorough drainage of the subsoil, and this can usually be obtained by digging away a foot or two of the soil before any rocks are laid, and placing a layer of broken stones, etc. of various sizes before the soil is replaced. It must not be forgotten that in the Alps the plants grow, for the most part, in naturally drained places, where water does not stagnate. In the long Alpine winter they are kept dry and at a fairly even temperature by a deep coating of snow; and when spring arrives, the melting of the snow around the plants gives them a good start, while as the growing season advances the deeply penetrating roots are given a copious supply of water from the ever-melting snow above, which moisture sinks into the porous ground or trickles down the mountain slopes. Therefore, in our gardens, the first thing to guard against is excessive moisture in winter - we can well imagine the numbers of 'Alpines ' which have been killed by the persistent rains of the present winter, 1911-12. The second precaution must be made in spring. In early spring there is a danger of some of the more delicate subjects being shrivelled up by cold east winds and brilliant sun, so that they should be watered carefully and only when there is no sign of frost.
As early summer approaches most 'Alpines' should be well watered once or twice a day.
Much can be done in order to protect some plants from the effects of our damp and comparatively sunless winter. Sometimes if a piece of glass or slab of stone be placed in a horizontal position above delicate plants they will be protected from excessive rainfall or drip. The soil around the base of the stems or rosettes of leaves should not be allowed to become clogged and foul, or coated with green liverwort, moss, or other weeds. This can be easily prevented by carefully disturbing the top soil, removing the moss, etc., and top-dressing with grit, sandy loam, bits of limestone, sandstone, or sometimes a dressing of leaf-mould. This top-dressing is of the greatest importance, and when done judiciously it cannot fail to be of benefit. It applies even more to young plants in pots or boxes in greenhouses and frames, for it is in such places that the growth of liverwort, etc., is often most rapid.