This section is from the book "The Gardener V3", 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.
The rainfall of the past summer, and the thick clouds in which the sun has been enveloped for the greater part of the season, have left gardeners with a legacy on their hands to make up by artificial conditions the deficiencies of a cold sunless summer before the short days of winter are upon us.
After such a prolonged season of cold and wet, the autumn may yet come in fine; and if our hopes should be realised, and the heavy clouds should disappear only for a short season, the opportunity must not be lost to assist nature artificially to make a climate which will complete and consolidate the growth of plants. Shade, with its attendant consequences on plants, whether it be from the absence of sun and light, or whether the latter be excluded by artificial means, permanently or in part, forms a feature in practical gardening which is of more importance than many people would suppose, notwithstanding the part it plays in the ultimate return that plants will yield in the way of flowers. The present season has been a most difficult one to manage in this respect, owing to the soft nature of the growth that most plants of a succulent tendency have made, both out of doors and under glass. The rough-and - ready makeshift of shading glass with lime, which has to answer in ordinary seasons, is a practice that, this year, will not commend itself to the observation of those who understand the influence that solar heat and light have upon plants.
On the one hand, shade is indispensable even to plants that in ordinary seasons do not require it; and, on the other, the shade should be of the thinnest possible texture compatible with safety to the plants, and be used only for a short time during the hottest part of the day.
Plants that are planted out for the summer are the worst to manage this season, owing to their growth being retarded by the inclement weather in the early part of the year, and which is consequently soft, and will require skill to perfect and mature it. This refers to Salvias, Solanums, Eupatoriums, Deutzias, Bouvardias, etc.
The cure for these will be to have them lifted early and put under glass in a shaded aspect, and keep them rather close and syringed until the roots begin to work - a process which will only occupy a few days - and then place them in the warmest and brightest position that can be afforded them under glass, full in the sun, and set them thin enough apart for air to play about them on all sides. It is possible that, under the changed conditions, the plants will require a little extra attention, especially if the days are bright; but they will gradually become hardened, and with a partial cessation of root-growth, the tissues of the shoots will soon "fill up firm,' and turn hard to the feel. Of course the tops of Solanums will have been pinched out, so that the flow of sap will have been directed to the formation and swelling of the berries, and other plants will have been treated according to their several requirements.
We have a capital example of the advantages of growing plants under glass in a season like the present, in two sets of Deutzias, which looked dead in the beginning of last May. The plants were cut down right to the bottom, and plunged in bottom-heat, which was increased as symptoms of active growth appeared, and continued till the shoots had grown to their full length and changed to a sort of greenish-white, which is the first indication that growth is complete, and that atmospheric conditions must be altered. These plants were exposed by stages, and are now plunged full in the sun in the open air, and are as brown as hazel; whilst their neighbours, cut down at the same time, and planted in a south border, are as green as Leeks.
The general body of plants for winter flowering will need more than ordinary care this autumn in order to prepare them for the winter; for although they may look quite green and fresh now, their soft leaves will not stand long when the days arrive at their shortest, unless they are well exposed to air and light, and the natural warmth of the autumn assisted with fire-heat.
It may also be expected, as an unpleasant contingency, that plants, like other things, will flower late this autumn, so that the gardener had better prepare himself for the emergency by anticipating events.
In the autumn there are Chrysanthemums which are grown by the hundred in many gardens, but which are considered objectionable as cut flowers in not a few places. There is, however, variety enough in a good collection to make a fine show in the conservatory, without drawing much upon other resources; and this compensates for the disfavour in which they are sometimes held as cut flowers.
Taking a rough glance at the prospect of cut flowers for early winter, we have forced Roman Hyacinths, the old white Azalea indica, and old plants of Bouvardias, in scarlet and white, which are indispensable subjects in every garden.
Old plants of the latter are decidedly preferable to young ones for autumn flowering, and should be kept growing up to about the beginning of October, not in a strong heat, but in an aspect where the wood will not turn hard, but continue to furnish an abundance of shoots, which in turn will supply quantities of flowers of transcendant merit for all purposes of decoration. A batch or so of Zonale Pelargoniums (old plants) brought into heat about the same time will supply scarlet flowers until Poinsettias and Plumbagos come in; and a batch of spring-struck Pelargoniums will continue to flower up to February, if kept in a cosy little house near the glass, and well supplied with liquid manure and plenty of fresh air. Eucharis amazonica, for supplying winter flowers, should be chosen from the largest bulbs which have finished their growth about the end of September, and be kept barely on the move until the beginning of November, and plunged in a sharp bottom-heat, when every bulb, according to its size and development, will throw up a spike bearing from five to seven flowers.
A few plants of Imanto-phyllum miniatum treated in the same way will make a most effective companion for the Eucharis. Large plants of Gardenias that were cut back and pinched at two or three different times through the summer, with a view of securing a succession of blooms for the next six months, should be kept moving steadily; and young plants propagated this season, and intended for flowering early next summer, should (if their buds are not already set) be kept on the dry side at a mean temperature of 60°, so that they may set their flower-buds and progress satisfactorily for the purposes for which they are intended. Little plants of Torenia Fourneri, pegged down to about 6 inches high, make handsome little bushes for vases, or front rows for stands; and small plants of Clerodendron fragrans are useful for the same purpose. A batch of Begonia Fraetelli, raised from seed this season, are now coming in useful, their deep glossy leaves and bright flowers being attractive little subjects for mixed groups, say in company with small Maidenhair Ferns and Caladium argyrites brought forward for winter decoration.
Harrison's Musk, propagated late in the summer, and pegged over the surface of 6-inch pots, are handsome objects for covering the surface of large pot-plants when the growth hangs over the sides of the pots, and for front lines in small conservatories they are not surpassed. A batch of Tuberoses, when they are in stock, will help to make handsome button-holes, and are in great request for balls and parties in the absence of Gardenias. They require an intermediate temperature on the dry side, and in foggy weather make sure of a dry atmosphere by keeping the ventilators closed. Late Celosias will require to be kept near the glass in a light situation; their feathery sprays will be found invaluable six weeks hence for arranging with other plants and flowers. Heliotropes propagated in the beginning of the summer should now be fine bushes. The last pinching will have been performed about the end of August, and the plants being grown in the shade, will need to be gradually exposed and be brought into flower in a moderate warmth about November. These, with a bunch of Violets, a spray of Mignonette, and a single Eucharis, will make nice little bouquets for small glasses in bedrooms.
Dendrobium nobile that have changed to the colour of a sovereign will stand in a cool greenhouse full in the sun, and finish the ripening process better than if kept in heat. Keep the plants dry at the root when they are in a low temperature, but see that the growths do not shrivel.
Linum irigynum is better than ever we have had it, from cuttings sent us last June. The plants have been shaded from what little strong blinks of sun we have had, and have been kept growing up to the present date - September 9. The plants are free from spider, and are quite green. This is one plant that the dull weather has accommodated; but it too will require to be hardened and solidified before the winter.
Flowering Begonias, Justicias, Eranthemums, and all such plants with soft leaf-growth, will have to be well hardened by "making a long autumn" with artificial heat and warm air, and what little sunshine we can reasonably hope for before winter. W. Hinds.