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 very rarely see the cause of hardy annuals advocated in our periodicals. Now and again we see a notice of one or two new introductions, with a few passing comments on their merits, but the tone of these comments unmistakably shows that annuals are subjects of only second-rate importance in fashionable flower-gardening. Their inexpensiveness, and the ease with which they may be cultivated generally, have prevented them from being so utterly neglected as hardy perennials have been; but for many years amateurs have been their chief patrons, and they have received very little favour, especially in the better class of gardens, from professionals generally. Now, however, that there are signs of a turn in the tide in favour of introducing more variety in form and colour, as well as subjects likely to prove attractive on other accounts than colour simply, we may fairly hope hardy annuals will come in for a fair share of attention. It would be superfluous to insist on their beauty; no one that has ever seen hardy annuals really well grown can have any other opinion than that in their ranks are to be found a goodly array of Flora's choicest gems.
In general, light graceful beauty is their characteristic; they lack the boldness and sustained brilliancy of the favourite types of bedding-plants; but this fact should be all in their favour in the view of those that desire to make some reform in their flower-gardening. As a class they can never vie with bedding-plants for the purpose of massing; a very few, perhaps, may be useful in that way, in cases where it is difficult or impossible with the available means to rear full complements of tender plants. They are only suitable for planting in the mixed style in which density of general effect must give place to individual attractions. They may be best employed in filling up blanks in herbaceous borders, and in ornamenting the edges of beds of shrubs, and some few are very beautiful rock-work plants. Many of them bloom very early, and may be had in flower a few weeks after sowing; and a very important group - the "Californian Annuals" - by means of autumn sowings, can be brought into flower so early in many of the favourable districts, that they may be made available in spring flower-gardening; and even in the least mild parts, if a cold frame may be devoted to them during winter, they will serve, along with other hardy plants, to make beds and borders gay long before bedding-plants can be turned out into summer quarters.
While the writer thinks it desirable that hardy annuals generally should receive a greater amount of attention, he has personally more favour for the "Califor-nians " than for those other hardy annuals which, hailing from many countries superior in respect of climate to our own, can only be cultivated during summer with us; and it is to this group that the remainder of the present paper will be devoted. The different species comprised in the group are not all natives of California, but a large proportion of them are so. All submit to the same general treatment, and the term Californian Annuals is therefore sufficiently applicable and convenient in a general sense. The beauty and profusion of the flowers of many of them are remarkable when they are well cultivated and attended to. The names of a few of the most popular among them, such as Limnan-thes, Nemophila, Clarkia, Godetia, Eutoca, and Whitlavia, need only be mentioned in proof of their first-rate ornamental qualities. These contain some of the most choice and brilliant of hardy annuals, but they by no means monopolise the beauty of either the group to which they belong, or the whole class of hardy annuals. The Californians succeed best when sown in autumn in most parts of the country.
I have often had splendid plants from self-sown stock of Limnanthes, Nemophila, Collinsia, and others in bloom in April in Scotland; and with careful attention to the removal of decaying flowers along with the seed-vessels as they formed, they have lasted in ornamental condition till July and August, when late spring-sown plants came in to take their place, and keep up the display to the close of the year. Many of them freely sow themselves, especially in light warm soils and early districts. Advantage may be taken of this in transplanting as many seedlings as may be required to a nursery-bed, in some sheltered corner, where they must be kept till the rigour of winter is spent. In less favourable districts, however, throughout the greater part of Scotland, and many parts of England also, although autumn-sown plants may scatter their seeds, and give rise to a number of plants, they are usually either too far advanced, or too late to winter well; in the one case being too gross, and in the other too small, to withstand the effects of long-continued frost and damp. It is better, perhaps, in every case, to sow regularly, so as to insure a prospect of ample stock to transplant the following spring.
The beginning of September is early enough to make the sowing; and the poorest piece of ground that can be chosen, if well sheltered and warm in aspect, is the best for the autumn seed-bed. If the ground is poor, sandy, and dry, so much the better; digging and sowing, either in drill or broadcast, is all that is necessary in this case. But if rich and retentive, it will be necessary to reduce the staple by the addition of sand, lime, rubbish, or fine-sifted ashes; and further, in order to secure the best possible drainage for the young plants, it will be advisable to raise the bed in the centre-ridge fashion. If all this is needed, drill-sowing is the best in the circumstances; and the drills should be ranged across the ridge, not along it, because the plants will thereby enjoy greater variety of aspect, and will be also less liable to suffer from stagnation at all points of the drill, for the top of the ridge will always be in a tolerably well-drained condition in even the most unfavourable cases. Wherever a line can be sown along the base of a west or south wall the plants may be expected to do well, and to come very early into flower the following spring. In severe weather, long continued, they will require some kind of protection.
A few saplings hooped over the bed, so as to support mats, or well-clothed Spruce branches, will be found quite sufficient covering in ordinary winters in any locality; and these coverings should only be put on when the weather is so severe as to cause apprehension of destruction to the plants, and be removed again as soon as it improves. The plants will require to be thinned before winter sets in, so as to stand quite clear one of another; and some attention will be needed from time to time afterwards to keep them quite free from decaying leaves, and any other cause of damping that may find a place among them. Those that can devote handglasses or cold frames to the wintering of them will have their prospects of success increased, and will, besides, be rewarded by the earliest possible crop of flowers. Under glass they will require similar treatment to Cauliflower, Calceolarias, or Pentstemons. Give air at all times except during the most severe weather. Remove the lights wholly on bright mild days, and keep them on, but tilted, in wet ones. Give water sparingly, only enough to prevent flagging, till the days lengthen and the plants begin growing vigorously. In March they should undergo a process of hardening off, so that they may be planted out in April as early as possible.
If they have been wintered in the open ground they will require no hardening off preparatory to planting out, but any protection that may have been given to the seed-bed should be removed a few days beforehand; and in the event of bad weather setting in after planting out, it will be advisable to stick a spray of Spruce close to each plant so as to arch over it. The first spring sowing will be early enough made in the end of April, and a second may be made the first week of June. The latter should be made on a west or east aspect, where the plants will come away more vigorously than if sown in full exposure to the sun. All that may be transplanted with safety may be sown in the ground either broadcast or in lines; and tap-rooted kinds that do not succeed well when transplanted, must be sown where they are to remain, or in pots, to be turned out with balls.
The following short list comprises a few of the best of the Cali-fornian annuals. Those marked with an asterisk are not in every case the most beautiful, but they are all worthy of being cultivated in any garden, and are specially marked as being the longest bloomers, some of them blooming for a very long period indeed, if a little care is bestowed in picking off the seed-pods, and on watering in periods of drought: -
" " alba - same as species, but white-flowered.
Callichroa platyglossa - 1 foot, bright yellow. Centaurea depressa - 1 foot, deep blue.
" " rosea - same height as species, centre florets rose, outer ones blue. *Clarkia pulchella - 1½ foot, in variety.
*Calliopsis tinctoria - 2 feet, yellow and dark crimson and brown, in variety. Collinsia bicolor- - 1 foot, lilac and white.
" " candidissima - pure white, same height as species.
" multicolor - 1 foot, deep lilac and white. " verna - 1 foot, blue and white, the best and earliest. Eucharidium grandiflorum - 1 foot, deep rose-purple.
*Eschscholtzia compacta - 9 inches, bright yellow, with deep saffron base to petals.
* " tenuifolia - 1 foot, sulphur. Eutoca viscida - 1 foot, deep blue.
*Gilia tricolor - 1 foot, pale purple, shaded.
" " alba - same as last, but with white margin to corolla. Godetia lepida - 1 foot, pale lilac and deep purple, shaded, " Lindleyana - 1½ foot, rosy purple.
" roseo-alba - 2 feet, rose in centre, dull white on margin of petals, " rubicunda - 2 feet, lilac purple. Koniga maritima - 9 inches, white.
Leptosiphon androsaceus - 6 to 9 inches, variously coloured from white to purple, " aureus - 6 to 9 inches, golden yellow, " luteus - 6 to 9 inches, pale yellow.
Limnanthes Douglassii - 6 to 9 inches, trailiog petals, with yellow base and white margin. " " alba - same as species, but pure white.
*Lupinus nanus - 9 to 12 inches, purplish blue, white, and rose. Malcomia maritima - 6 inches, variously shaded with rose purple and white. Nemophila insignis - 6 to 9 inches, trailing, sky-blue, with white centre.
* " " alba - 6 to 9 inches, pure white.
" maculata - 9 inches, white, with purplish-black spots.
Platystemon californicum - 9 inches, trailing, sulphur. Osyura chrysanthemoides - 9 inches, bright yellow. *Silene vespertina - 1 foot, rose-coloured. Specularia pentagonia - 1 foot, violet and white. Viscaria oculata - 1½ foot, rosy purple. Whitlavia grandiflora - 1 to 1½ foot - deep blue. Wm. Sutherland.