AURANTIACEÆ. An order of trees or shrubs, including the Orange and Lemon trees. Flowers fragrant. Fruit fleshy, edible. Leaves alternate, articulated above the stem, filled with transparent oil cysts, giving them a dotted appearance. Well-known genera are Citrus and Limonia.
AURICULA (Primula Auricula). This favourite spring flower (see Fig. 195) was, at one time, almost universally cultivated, but has of late years fallen into much neglect; it is now, however, happily regaining enthusiastic admirers. Although its culture is not nearly so difficult as is generally understood, a few special items of treatment are nevertheless necessary to grow it successfully.
FIG. 195. A VARIETY OF PRIMULA AURICULA.
Frames for the reception of Auriculas should be prepared, with a good bottom drainage, and an inside staging, similar to the back stage of a lean-to greenhouse, arranged as near the glass as possible. If the frames are about 4ft. wide, they will be very convenient; 1ft. deep in the front, and about 3ft. at the back. This will allow for a good stage arrangement. Of course, it is not necessary to construct an expensive staging, as common boards can be laid upon pots of various heights, the same results being practically secured. These frames should face north from May to October, and south in winter, during which latter time it will be necessary to well cover the sides with straw or brake. When frosty, the lights must also be mated; but, unless there is absolute fear of frost, the glass should not be covered, as the more light the plants receive the better. On all suitable occasions, both during summer and winter, air must be freely admitted, and a good look-out kept during showery weather; hence it may be necessary to tilt the lights with blocks rather than remove them entirely. The latter plan should be adopted whenever practicable, especially during early spring, and after they are well established in their fresh pots in summer. This will greatly assist to ripen the crown, and produce hard, stout foliage, which will endure the winter much better than if grown with less air. Many cultivators prefer small span or lean-to houses to frames; and it must be admitted that these are better, more convenient, and in every way more beneficial. Simple, inexpensive structures, no higher than is absolutely necessary for convenience, with top and side ventilation, will meet all requirements; and if a 2in. hot-water pipe is arranged next the eaves inside, it will be a decided advantage during very severe weather.
Soil. The best compost that can be prepared for Auriculas is as follows: Four parts good fibrous loam, one part well-rotted cow manure, one part good leaf soil, and one part coarse river or silver sand, with a little charcoal or pounded oyster-shells added. Carefully mix the whole together before using. The loam should be stored about twelve months previous to being used, and it should be selected from districts with a fine atmosphere; the turf should be cut about 3in. thick. Cow manure that has lain for a year or so, and been subjected to sharp frosts, is most suitable, as insect life, which it very probably contains, is thereby destroyed, and the whole materially sweetened.
Potting. This operation requires to be carefully done as soon after flowering as possible, unless it is desired to save seed, when it must be deferred until the seed is ripened. May and June are the best months for general potting, and whatever the size of the pots used, they should be carefully and thoroughly drained. After a good layer of potsherds, place some charcoal, leaf mould, or spent hops. Many good growers use the last very advantageously. For good flowering plants, 48-sized pots are used, many cultivators preferring glazed pots to the unglazed; but such are not absolutely necessary to ensure success. Before repotting, remove most of the old soil, and with a sharp knife cut off any bruised or cankered portion of roots; the stout tap-root may also be cut away if devoid of fresh rootlets. Do not pot very firmly. Remove the plants to their summer quarters, withholding water for a few days, and keep the frames close. About a week after potting, water may be advantageously given, the plants will then soon resume root-action, and air may be admitted afterwards on all suitable occasions. The collar or neck of the plant must be left well above the surface of the soil.
Watering is a point that requires careful attention, as neglect in this matter will result in failure. During the growing season, Auriculas require an abundance of water; in fact, they must never be allowed to get dry. In the winter, they must only be watered when they are really dry, especially during a severe season. Care must be taken to avoid watering the leaves, particularly in early spring, as this tends to spoil the effect of the charming farinose foliage. Above all, water must not be allowed to stand in the heart of the plant, as such will inevitably cause incipient decay. Hence it is necessary to keep a sharp lookout for drippings from the glass, and to maintain tightly-glazed frames. On all occasions, decaying leaves must be removed, and especially during winter.
Top-dressing. About the middle or end of February, when the plants commence new growth, the surface soil should be removed about an inch or so deep, and the pots re-filled with a rich compost made up of the following: Two parts of turfy loam, one of rotten cow or hen manure, and one of leaf soil; if a little Standen's Manure is added, the compost will be improved. After this top-dressing, the plants may be watered freely.