Chapter 28

The Elegans varieties are of special value when treated as pot plants for conservatory decoration in May and June. From seed sown in August or early in September the plants can be slowly grown into magnificent specimens four feet high and almost as much in diameter. Our own practice is to sow thinly in clean well-drained 48-size pots. These are placed in a temperature of from 50° to 55°, and when the seedlings are large enough to handle they are pricked off into shallow boxes about three inches apart, the base of the boxes being freely perforated to insure ample drainage. The most suitable soil is composed of equal parts of sound loam and leaf-mould, with the addition of a gallon of coarse sand to each bushel of the mixed soil. After the plants are well established, ventilate freely to secure robust growth. When three inches high pinch out the points, and a little later transfer separately to small pots, keeping them close for a few days and as near the glass as possible. As the roots develop, transfer again to larger pots, and then the second and final stopping of the shoots must be done. Should very large plants be wanted they can be flowered in 16-size pots, using a compost slightly heavier than that advised at a younger stage of growth. The night temperature during winter should be about 45º, giving air freely by day whenever possible to do so with safety. As the branches need support, sticks of a suitable length must be provided, and the stems tied out in good time to prevent them from breaking off.

CLERODENDRON FALLAX

Stove shrub

A very handsome erect shrub, which is extensively grown in tropical gardens. In this country it attains a height of about two feet, and is easily raised from seed in a warm greenhouse or conservatory, where it proves to be a really beautiful and striking plant.

Sow in pots or pans in March or April and transfer to single pots while small. From the commencement a very rich soil is necessary to insure robust growth and intense colour in the panicles of brilliant scarlet flowers. The plants bloom in August or September of the same year. When the leaves fall, if the intention be to store through winter, remove to a temperature of 55°; but raising plants annually is more satisfactory and entails less trouble than storing.

Like many other tropical plants, Clerodendron fallax is subject to attack by mealy bug, and this pest may be dealt with by hand picking or by washing the leaves with insecticide two evenings in succession. Aphis are also troublesome and should be cleared by fumigation.

COCKSCOMB

Celosia cristata. Tender annual

This fine old-fashioned flower has won renewed popularity of late years, probably as the result of a number of well-grown plants exhibited at horticultural shows. Those who can produce handsome Cinerarias, Balsams, and Calceolarias, will be likely to turn out grand Cockscombs, strongly coloured and on dwarf, leafy plants. Liberal culture is essential, and the first start should be made in a compost consisting mainly of rich light friable loam. Sow the seeds on a rather brisk heat in February or March, a newly-made but sweet hot-bed being the best place for the seed-pans. Prick out early into very small pots, and shift on so as to encourage growth without a check, and keep the plants on the hot-bed until the combs are formed. It is well not to shift beyond the 8-1/2-inch size; then, by allowing the roots to become pot-bound, the combs are soon produced. It matters not how select the seed, or how careful the culture, a certain proportion of unsymmetrical combs will appear; but these, if richly coloured, will be useful for decorative purposes, and should have all the attention needed to keep their leaves fresh and the combs pure in colour.

COLEUS

Stove perennial

There is so much difficulty in carrying Coleus through the winter in vigorous health that the modern plan of treating it as an annual is advantageous for the saving of trouble and fire-heat in winter, and also because it offers the charm of constant diversity. The fact is that our winter days are too short and gloomy to maintain the splendour of colouring which makes Coleus so attractive and valuable; and seed from a good strain may be relied on to produce plants which will delight the eye all through the summer and autumn. Some experienced men sow in February and succeed, but the majority of cultivators will show prudence by waiting until March, when increased daylight favours the rapid growth of the plants. Flowerpots are better than pans, as the greater depth affords opportunity of securing effectual drainage. The pots should be nearly half-filled with crocks, covered with a layer of moss to prevent the soil from being washed away. Fill them with light turfy loam, mingled with almost an equal bulk of sharp sand. Make an even surface, on which sow thinly, and shake over the seed a slight covering of fine soil. Place the pots in a temperature of not less than 65°. Watering needs particular care, because of the peculiar liability of the young plants to damp off, especially in dull weather. The strongest seedlings are pretty certain to be those in which green and black predominate, and they may without scruple be removed to make way for the slower-growing but better-coloured specimens. These should be transplanted round the edges of pots while quite small; and such as show delicate tints, especially those having pink markings on a golden ground, are worth nursing through the early stage with extra care. The pots must be shaded from direct sunshine, but should be kept near the glass. In May the plants will be large enough for 48-sized pots, beyond which there is no occasion to go. When the pots become full of roots the foliage increases in brilliancy, whereas larger pots encourage free growth to the detriment of colour. A dry atmosphere is particularly injurious, while an occasional dose of manure water will maintain the plants in health.

COLUMBINE—_see_ AQUILEGIA

COSMEA

Cosmos. Half-hardy annual

Cosmeas make a striking show in the mixed border, and the flowers are also in large request for indoor decoration. Disappointment is often caused, however, through the plants failing to bloom until late in the season, and therefore it is important to grow an early-flowering strain in order to insure a long-continued display. The most successful method of raising plants is to sow the seed in pots during February, pricking off the plants as soon as large enough. When the first flowers appear in May, transplant to positions in the open immediately danger from frost is past.

CYCLAMEN

Half-hardy perennial

Gardeners of experience will remember the time when the predominant colours of Cyclamen were purple and magenta, and it was impossible for the most friendly critic to feel enthusiastic concerning these flowers. But the new colours—Salmon Pink, Salmon Scarlet, the intense Vulcan, Rose Queen and Cherry Red, together with Giant White and White Butterfly—are now regarded as the brightest and most beautiful decorative subjects for the long period of dark winter days of which Christmas is the centre. As cut flowers for the dinner-table Cyclamens have no rival at that period of the year, and as specimen plants in the home they are delightful for their free-flowering habit, compact form, and elegant foliage.

Seed may be sown at any time during autumn or the early part of the year, and the plants will not only flower within twelve months, but if properly grown will produce more bloom than can be obtained from old bulbs. We do not advise more than three sowings, the first and most important of which should be made in August or the beginning of September. To obtain a succession of plants, sow again in October and for the last time early in the new year. Those who have not hitherto grown Cyclamen for midwinter blooming will be well pleased with the result. It is quite as easy to flower them in the winter as in the longer days, and this is more than can be said about most plants.

The best soil for Cyclamen is a rich, sound loam, with a liberal admixture of leaf-mould, and sufficient silver sand to insure free drainage. Press this mixture firmly into pots or seed-pans, and dibble the seed about an inch apart and not more than a quarter of an inch deep. Cover the surface with a thin layer of leaves or fibrous material to check rapid evaporation, and later on keep the soil free from moss. The autumn sowings may at first be placed in a frame having a temperature of not less than 45°. At the end of a fortnight transfer the pans to any warm and moist position in the greenhouse or propagating house.

Although the Cyclamen is a tender plant, it does not need a strong heat, and will not endure extremes of any kind. Sudden changes are always fatal to its growth. In winter the temperature should not be allowed to fall below 56°, or to rise above 70° at any time. The more evenly the heat can be maintained the better, and it is desirable to give all the light possible. In summer, however, although a warm and humid atmosphere is still necessary, the light may with advantage be somewhat subdued, but shading must not be overdone, or the constitution of the plant will suffer.

Cyclamen seed not only germinates slowly, but it also grows in the most capricious manner; sometimes a few plants come up long after others have made a good start. Do not be impatient of their appearance, but when some seedlings are large enough for removal transfer to thumb pots, taking care not to insert them too deeply. As the plants develop, shift into larger pots, ending finally in the 48-size. In the later stages mix less sand with the soil, and when potting always leave the crown of the corm clear. Keep the plants near the glass, and as the sun becomes powerful it will be necessary to provide shade and prevent excess of heat. Never allow the seedlings to suffer from want of water, or to become a prey to aphis. To avoid the latter, occasional, or it may be frequent, fumigations must be resorted to. About the end of May should find the most forward plants ready for shifting into 60-pots. Give all the air possible to promote a sturdy growth. In doing this, however, avoid draughts of cold air. From the end of June to the middle of July the finest plants should be ready for their final shift into 48-pots, in which they will flower admirably. The growth during August and September will be very free, and then occasional assistance with weak manure water will add to the size and colour of the flowers. As the evenings shorten, save the plants from chills, which result in deformed blossoms.

The whole secret of successful Cyclamen culture may be summed up in a few words: constant and unvarying heat, a moist atmosphere, and abundant supplies of water without stagnation; free circulation of air, avoiding cold draughts; light in winter, and shade in summer, with freedom from insect pests. These conditions will keep the plants in vigorous growth from first to last, and the result will be so bountiful a bloom as to prove the soundness of the rapid system of cultivation. This routine may be varied by the experienced cultivator, but the principles will remain the same in all cases, because the natural constitution of the plant gives the key to its management.

DAHLIA

Half-hardy perennial

Both the double and the single classes of Dahlia are increasingly grown as annuals from seed, and this practice has the great advantage of being economical in time and in the saving of space during winter. The seedlings grow freely and quickly, and will flower quite as early as those grown by the more lengthy and troublesome method from tubers. Even those who possess a stock of named sorts may with advantage raise a supply from seed, especially as there is a probability of securing some charming novelty, which is in itself no small incentive.

Although the Dahlia is a tender plant, it is easily managed in a greenhouse, or in a frame resting on a hot-bed. The seed may be sown as early as January, but unless sufficient space is at command to keep the plants stocky as they develop, it will be wise to wait until February. A sowing in the month last named will produce plants forward enough to bloom at the usual time. Even March will not be too late; but whatever time may be chosen, when the start has been made it must be followed up with diligence, so as to avoid giving any check from first to last. Sow thinly in pots or pans filled with ordinary light rich compost, and cover the seed with a mere sprinkling of fine earth. When the first pair of leaves attain the height of an inch, pot off each plant singly close up to the base of the leaves. It is not advisable to throw the weakly seedlings away; these are the very plants which are most likely to display new shades of colour and they are worth some additional trouble. Although weak at the outset, they may, by judicious treatment, be developed into a thriving and healthy condition.

When potted, place the plants in heat, giving a little extra care until growth is fairly started. In due time shift into larger sizes as may be necessary, and then it will be wise to consider whether there is space to grow the whole stock well. If not, do not hesitate to sacrifice the surplus, and in doing so reject the rankest-growing specimens, for these are least likely to produce a fine display of bloom. It is mistaken practice to take out the top shoot, as this checks the plant for no good end; but when about six inches high, each one will need the support of a stick. Give water freely, and air on all suitable occasions. The least tendency to curled leaves indicates something amiss, and demands immediate attention. A cold blast may have stricken the plants, or the soil may be poor; lack of sufficient water will produce the mischief, or it may arise from the presence of aphis. If the last-named assumption prove correct, fumigate on the first quiet evening, and omit watering on that day. The mere mention of the other points will be sufficient to show the remedy for them.

As the time for transfer to the open air approaches, all that is possible should be done to harden the plants for the change. They may be placed for a few days under the shelter of a wall or hedge, but on the least sign of frost be prepared to protect with hurdles or mats. Full exposure during genial showers and fair weather is advisable, and an occasional examination of the plants will prevent their rooting through the pots into the soil.

The border for Dahlias can scarcely be made too rich, for they are hungry and thirsty subjects, and will amply repay in a profusion of bloom the manure that may be lavished upon them. Slugs and snails are unfortunately too partial to newly planted Dahlias, but the vermin soon cease to care about them; therefore it is advisable to plant Lettuces plentifully at the same time, or previously, on the same ground, and to dust around the Dahlias with lime. Insert at least one stake, about a yard long, near each plant, to give support, and two or three others will have to be given before the branches spread far. Secure the first shoot when planting is completed, and follow up the tying as growth demands.

Dahlias bloom continuously for a long time, and appear to be especially at home in the shrubbery border, or in the centre of a bed. They are also valuable for training against buildings having a southern aspect, and here the flowering period is much prolonged, for an early frost will scarcely reach them. A light wall is an admirable background for deep-coloured varieties, and the white or yellow flowers are displayed to advantage against a dark building. Dahlias may be used either alone or in company with the climbing plants which are usual in such positions.

The flowers possess a special value for indoor decoration, and any odd corner of the garden can be utilised for producing a supply for this purpose. Cutting should invariably be done in the early morning, while yet the dew is upon them. They will then retain their beauty for a longer period than those taken at a later hour from the same plants. This remark is true of all flowers, but it applies with especial force to the Dahlia.

DAISY, DOUBLE

Bellis perennis fl. pl. Hardy perennial

The remarkable development of the Double Daisy in recent years has raised this simple garden subject to the foremost rank of spring bedding plants. So pronounced has been the improvement achieved in the size and form of the flowers, that plants raised from a reliable strain of seed will now produce blooms which may well be mistaken for specimens of finely shaped Asters. When massed in a large bed the flowers present one of the most striking sights to be seen anywhere in the spring garden. But apart from their use in formal beds and borders, Double Daisies make a pleasing break among Wallflowers, and are particularly attractive when grown as an edging to bulbous flowers and other spring-blooming subjects such as Polyanthus, Myosotis, &c. Plants from a sowing made in pans in April and put out when large enough, may be flowered in the autumn of the same year. But the method more generally practised is to sow on prepared beds in the open during June or July, and to transfer the seedlings when sufficiently developed to positions for blooming in the following season.

DELPHINIUM

Hardy perennial

Nearly all the perennial varieties may be raised from seed, and where large numbers are required this is the best method of obtaining them. They make handsome border flowers, and are extremely valuable during the early months of summer. Sow in May, June or July, in the open ground, and transplant in autumn. If mixed seed has been sown, it will not be wise to thin out all the weakly plants, or it may happen that some of the choicest shades may be lost. The first flowers will be over by midsummer, but if the stalks are promptly cut down instead of being allowed to seed, there will be a second display later in the year.

Three varieties, Queen of Blues, Dwarf Porcelain Blue, and Blue Butterfly, may be flowered as annuals, by sowing in pans in March and transplanting to the open as soon as the seedlings are ready. They also make particularly charming pot plants, for which purpose it is advisable to sow seeds in March.

The scarlet variety (_D. nudicaule_) is rather more delicate than the others, and it is wise to raise the plants in well-drained seed-pans, and to take care of them through the first winter in a cold frame; indeed, in a heavy soil there is a risk of losing them in any winter which is both cold and wet. It is not necessary to employ pots, but immediately after flowering take them up and store in peat until the following April, when they can be returned to the open ground.

_D. sulphureum._ The seed takes a very long time to germinate, and severely taxes the patience of the sower. But otherwise there is no difficulty in raising plants, and the long spikes of beautiful clear sulphur-yellow flowers are well worth the extra time the seedlings need. The best plan is to sow in autumn in the open ground, cover with a frame, and avoid disturbing the soil, except for weeding, until the next autumn, when the plants should be put into position for flowering in the following summer.

As slugs are exceedingly partial to Delphiniums, the crowns should be examined in spring, and the seed-beds may be dressed with soot and surrounded with ashes to save the seedlings from injury.

The annual Delphiniums are dealt with under Larkspur, page 274.

DIANTHUS

Pink. Biennials, hardy and half-hardy

Many varieties of Dianthus claim attention for their elegant forms and splendour of colouring. They have been so wonderfully improved by scientific growers that they almost supersede the old garden Pinks, and have the great advantage of coming true from seed. _D. Heddewigii_ (Japan Pink) and its varieties, _D. chinensis_ (Indian Pink) and _D. imperialis_, make interesting and sumptuous beds, and may all be flowered the first year from sowings made in heat in January or February. Immediately the seedlings are through the soil it is important to shift them to a rather lower temperature than is necessary for insuring germination, or the plants become soft and worthless. Be very sparing with water, especially if the soil is at all retentive. When two leaves are formed, transfer to pans, allowing about an inch between each plant, and place in a sheltered position. Gradually introduce to cool treatment, and when ready prick off again, allowing each plant more space. They will thus have a much better start, when planted out in May, than if taken from the seed-pans direct. Dianthus make a most attractive display in pots, and a number of seedlings should be potted on for flowering in this manner.

Where there are no facilities for raising Dianthus in heat, it is quite easy to grow plants in an open spot from a sowing in June or July, and they will flower freely in the following year. Prepare drills about six inches apart and line them with sifted soil; sow thinly, and carefully cover the seed with fine soil. Shade must be given during germination, but it should be gradually withdrawn when the seedlings are up. Transfer to final positions in August. Should this be impossible, prick the plants out, and shift them again a little later. It will only do harm to leave them crowded in the seed-bed, and the second move will better enable them to withstand winter frosts. The Dianthus thrives in a sandy or loamy soil, with full exposure to sunshine, and the plants scarcely need water or any attention the whole season through.

DIGITALIS

Foxglove. Hardy biennial

Besides the native Purple Foxglove, largely grown in gardens, there are several very handsome varieties that are valuable for adorning borders, shrubberies and woodland walks. Specially worthy of attention are Giant Primrose, a beautiful variety with rich cream or buff flowers; the Giant Spotted, which produces handsome flowers, rich and varied in colour; and the white variety with its abundance of charming ivory-white bells, which are occasionally slightly spotted.

Any deep rich soil suits Digitalis, and seed sown in May, June, or July will produce seedlings which, with very little attention, will yield a fine display of flowers in the following summer. Sow in the open in pans, or on a prepared border, and put the young plants into permanent positions, choosing showery weather in August or September.

DIMORPHOTHECA

Half-hardy annual

The Dimorphotheca, also called the Star of the Veldt, was introduced into this country from South Africa and, like the Nemesia, also a native of that Dominion, it has become one of the most valuable of our summer annuals. Under favourable conditions plants may be flowered in six weeks from time of sowing and they will continue to bloom in profusion until cut down by frost. In addition to the striking orange flower, _D. aurantiaca_ (Orange Daisy), a wide range of colours, including many delicate tints, has been evolved by careful hybridisation.

Those who wish to obtain forward plants should sow during March or April in pans of light soil placed in a cold frame, and the seedlings will be ready for transfer to open quarters in May. Or seed may safely be sown in the open ground in May and June. As suggested by its native habitat, the Dimorphotheca loves a warm sunny position and grows to the greatest perfection in a light soil or a well-drained loam.