CHRYSANTHEMUM  (Chrysanthemum sinense; nat. ord. Compositae), one of the most popular of autumn flowers. It is a native of China, whence it was introduced to Europe. The first chrysanthemum in England was grown at Kew in 1790, whither it had been sent by Mr Cels, a French gardener. It was not, however, till 1825 that the first chrysanthemum exhibition took place in England. The small-flowered pompons, and the grotesque-flowered Japanese sorts, are of comparatively recent date, the former having originated from the Chusan daisy, a variety introduced by Mr Fortune in 1846, and the latter having also been introduced by the same traveller about 1862. The Japanese kinds are unquestionably the most popular for decorative purposes as well as for exhibition. They afford a wide choice in colour, form, habit and times of flowering. The incurved Chinese kinds are severely neat-looking flowers in many shades of colour. The anemone-flowered kinds have long outer or ray petals, the interior or disk petals being short and tubular. These are to be had in many pleasing colours. The pompon kinds are small flowered, the petals being short. The plants are mostly dwarf in habit. In the single varieties the outer or ray florets alone are large and attractively coloured.
Plants for the Border. - As a border plant out of doors the chrysanthemum is of the easiest culture. It is an exceptionally good town plant. By a judicious selection of varieties, flowers may be produced in abundance and in considerable variety from August to the end of November, and in favourable seasons well on towards Christmas. Since 1890 when the English market was flooded with French raised varieties of exceptional merit, the border chrysanthemum has taken first place among hardy autumn flowering plants. Most of the varieties then introduced have been superseded by many excellent kinds raised in Britain.
Propagation. - The old English method of dividing the plants in March or early April may be followed where better means of propagation are not practicable. Many of the best border varieties are shy in producing new growths (suckers) from the rootstock, and are in consequence not amenable to this method. It is better to raise the plants from cuttings. This may be begun in January for the early flowering sorts, the late kinds being propagated during February and March. They will root quite well in a cold frame, if protected during frosty weather by litter or other similar material. If the frame can be heated at will so as to maintain a fairly even temperature of from 4O° to 50° Fah., roots will be made more quickly and with more certainty. A still better method is to improvise a frame near the glass in a greenhouse, where the temperature is not raised above 50° by artificial heat. This has the advantage of being accessible in all weathers. The bottom of the frame is covered with sifted coal ashes or coco-nut fibre, on which the shallow boxes or pots used in propagating are placed. These are well drained with broken crocks, the bottoms of the boxes being drilled to allow water to pass out quickly. The soil should consist of about equal parts of fibrous loam and leaf-mould, half a part of coarse silver-sand, and about a quart of vegetable ash from the garden refuse heap to each bushel of the compost. The whole should be passed through a quarter inch sieve and thoroughly mixed. The coarse leaf-mould, etc., from the sieve should be spread thinly over the drainage, and the boxes or pots filled almost to the rims with the compost, and covered, if possible, with a thin layer of silver-sand. It should be pressed firmly, watered with a fine rose, and allowed to drain for an hour. The cuttings should then be dibbled into the boxes in rows, just clear, the soil being gently pressed around each. Short stout shoots which arise directly from the rootstock make the best cuttings. In their absence cuttings from the stems are used. The ideal length for a cutting is about 2 in. Cut the stem squarely with a sharp knife just below a joint, and remove the lower leaves. Insert as soon as possible and water with a fine rose to settle the soil around them. The soil is not allowed to become dry. The cuttings should be looked over daily, decayed leaves removed, and surplus moisture, condensed on the glass, wiped away. Ventilate gradually as rooting takes place, and, when well rooted, transfer singly into pots about 3 in. in diameter, using as compost a mixture of two parts loam, one part leaf-mould, half a part coarse silver-sand, and a gallon of vegetable ash to every bushel of the compost. Return to the frames and keep close for a few days to allow the little plants to recover from the check occasioned by the potting. Ventilation should be gradually increased until the plants are able to bear full exposure during favourable weather, without showing signs of distress by flagging. They should be carefully protected at all times from cold cutting winds. In April, should the weather be favourable, the plants may be transferred to the borders, especially should the positions happen to be sheltered. If this is not practicable, another shift will be necessary, this time into pots about 5 in. in diameter. The soil should be similar to that advised for the previous potting, enriched with half a part of horse manure that has been thoroughly sweetened by exposure. Plant out during May. All borders intended for chrysanthemums should be well dug and manured. The strong growing kinds should be planted about 3 ft. apart, the smaller kinds being allowed a little less room.
In the summer, water in dry weather, syringe in the evenings whenever practicable, and keep the borders free from weeds by surface hoeings; stake and tie the plants as required, and pinch out the tips of the shoots until they have become sufficiently bushy by frequent branching. Pinching should not be practised later than the end of June.
Pot Plants for Decoration. - A list of a few of the thousands of varieties suitable for this purpose would be out of place here; new varieties are being constantly introduced, for these the reader is referred to trade catalogues.
The most important considerations for the beginner are (a) the choice of colours; (b) the types of flowers; (c) the height and habits of the varieties. Generally speaking, very tall varieties and those of weak growth and delicate constitutions should be avoided. The majority of the varieties listed for exhibition purposes are also suitable for decoration, especially the Japanese kinds. Propagation and early culture are substantially as for border plants.
As soon as the 5-in. pots are filled with roots, no time should be lost in giving them the final shift. Eight-in. pots are large enough for the general stock, but very strong growers may be given a larger size. The soil, prepared a fortnight in advance, should consist of four parts fibrous loam, one part leaf-mould, one part horse manure prepared as advised above, half a part coarse silver-sand, half a part of vegetable ash, and a quart of bone-meal or a sprinkling of basic slag to every bushel of the mixture. Mix thoroughly and turn over at intervals of three or four days. Pot firmly, working the soil well around the roots with a lath. The main stake for the support of the plant should now be given; other and smaller stakes may later be necessary when the plants are grown in a bushy form, but their number should not be overdone. The stakes should be as few as possible consistent with the safety of the shoots, which should be looped up loosely and neatly. The plants should be placed in their summer quarters directly after potting. Stand them in rows in a sunny situation, the pots clear of one another, sufficient room being allowed between the rows for the cultivator to move freely among them. The main stakes are tied to rough trellis made by straining wire in two rows about 2 ft. apart between upright poles driven into the ground. Coarse coal ashes or coke breeze are the best materials to stand the pots on, there being little risk of worms working through into the pots. The plants, which are required to produce as many flowers as possible, should have their tips pinched out at frequent intervals, from the end of March or beginning of April to the last week in June, for the main season kinds; and about the middle of July for the later kinds.
Towards the end of July the plants will need feeding at the roots with weak liquid manure, varied occasionally by a very slight dusting of soluble chemical manure such as guano. The soil should be moderately moist when manure is given. In order that the flowers may be of good form, all lateral flower buds should be removed as soon as they are large enough to handle, leaving only the bud terminating each shoot. Towards the end of September - earlier should the weather prove wet and cold - remove the plants to well-ventilated greenhouses where they are intended to flower. Feeding should be continued until the flowers are nearly half open, when it may be gradually reduced. The large mop-headed blooms seen at exhibitions in November are grown in the way described, but only one or two shoots are allowed to develop on a plant, each shoot eventually having only one bloom.
The chrysanthemum is subject to the attack of black aphis and green-fly. These pests may be destroyed, out of doors, by syringing with quassia and soft soap solutions, by dusting the affected parts with tobacco-powder, and indoors also by fumigating. Mildew generally appears after the plants are housed. It may be destroyed by dusting the leaves attacked with sublimed sulphur. Rust is a fungoid disease of recent years. It is best checked by syringing the plants with liver of sulphur (1 oz. to 3 gallons of water) occasionally, a few weeks before taking the plants into the greenhouse. Earwigs and slugs must be trapped and destroyed.
Flowers for Exhibition. - Flowers of exhibition standard must be as broad and as deep as the various varieties are capable of producing; they must be irreproachable in colour. They must also exhibit the form peculiar to the variety when at its best, very few kinds being precisely alike in this respect. New varieties are introduced in large numbers annually, some of which supplant the older kinds. The cultivator must therefore study the peculiarities of several new kinds each year if he would be a successful exhibitor.
For lists of varieties, etc. see the catalogues of chrysanthemum growers, the gardening Press, and the excellent cultural pamphlets which are published from time to time.
 The Gr. (Gr., gold, and , flower) was the herbalists' name for C. segetum, the "corn marigold," with its yellow bloom, and was transferred by Linnaeus to the genus, being commonly restricted now to the species C. sinense.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)