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.
Without doubt the Gardenia as an evergreen stove-plant stands very high in popular estimation, and is very highly prized by ladies for the sweet fragrance its flowers possess, as much so as the Rose, the Eucharis, and others - and more especially because it can be brought into bloom in autumn, winter, and spring. Although its flowers are only of short duration, they do not all open together, which makes them the more useful, as a large plant will continue to open blooms over a period of some weeks. With a number of plants, and care and forethought exercised in preparing or retarding them, as the case may be, the blooming of Gardenias can be extended over seven or eight months, provided a sufficient number of plants can be cultivated, and the plants are prepared for the various seasons. The natural blooming-time, if under ordinary stove treatment, will be through March, April, and May. To produce them in early autumn takes considerable time, more room, and a large number of plants to work upon.
The Gardenia is subject to all kinds of insects which infest plants, and if every attention is not paid to keep it thoroughly clean, much trouble and annoyance are caused, and in the end, instead of a crop of fine flowers, the cultivator reaps disappointment. This is perhaps the reason why the Gardenia is not more largely grown in some private places, especially where plant-houses are badly infested with mealy - bug, scale, and other insects, which seem at once to arrest the growth; and but little success can be anticipated. "When out of flower, well-grown plants in exuberant growth are beautiful to look upon, on account of the dark glossy foliage which is so characteristic of the plant when in good health.
The propagation of Gardenias can be effected at almost any season of the year from cuttings. These are by no means difficult to strike from the ripened wood. We, however, prefer striking about August from half-ripened wood, as this leaves the whole of the following year before us to start early in the season and grow the plants as large as possible. The cuttings are best inserted singly in small pots in a mixture of peat and sand, and plunged into bottom-heat until rooted in the propagating house or frame. If practicable, a little bottom-heat should be applied through the whole season up to the end of August. This will make the plants grow more rapidly, and produce nice bushes in 6-inch pots, if properly attended to in the way of watering, potting, stopping, and shading for a few hours during the hottest part of the day. In potting, the pots should be carefully drained, and a little moss, or a portion of the roughest part of the compost, laid over the crocks. The compost we find most suitable after the young plants are rooted and require larger pots is a rich fibry loam and peat, using a 6-inch potful of bone-dust to every barrowful of soil, and a good dash of sharp silver-sand to make the whole porous. The soil should be pressed firmly into the pots.
Keep the house or pit in which they are growing close until they have taken to the new soil. The atmosphere should be moist, and the plants well syringed overhead. If the plants are plunged, and the soil in moderately moist condition at the time of potting, the plants will not need watering, at least for a few days, which will give the fine roots of the Gardenia a chance of recovering from the damage received in potting. However carefully this operation is performed, it is next to impossible to do it without the roots receiving injury more or less; and if watered, which is too frequently done, the roots have not a fair chance of starting quickly into the new soil.
Avoid the too common practice of using a sharp -pointed stick to liberate the roots from the ball of the plants. In potting evergreen stove - plants - especially such fine-rooted subjects as the Gardenia - the crocks only should be carefully removed, and any little loose soil from the top of the ball. The new soil should be pressed firmly round the sides of the ball, so that water cannot pass through it and leave the old ball dry; the roots will enter the new soil freely enough, provided this is carefully done. The slaughtering system of using a sharp-pointed stick to set the roots at liberty cannot be too strongly condemned, as we believe more plants have to be conveyed to the rubbish-heap through this than any other cause, especially fine-rooted plants such as Heaths, and this caution applies with equal force to the Gardenia.
If the young plants are required to bloom the first season, they should not be stopped after August, but allowed to extend their shoots, and be grown from that time with a little more air. Under these circumstances the young plants will soon complete their growth, and form flower-buds, averaging from eight to ten blooms to each plant, which will come out during March, or earlier if brought on rapidly in a brisk heat after the buds are set. If the object be to grow the plants into a good size as quickly as possible, they should not be allowed to bloom, but be stopped later than the time named to prevent cutting the young growths back, and again get an early start the following year. If allowed to bloom, and two or three months are lost at the commencement of the year, a much longer time will be required to get the plants into a good size. It is best to sacrifice the bloom the first season; and after the commencement of the year, and root-growth has fairly commenced, they should be transferred into 8-inch pots, using the compost already recommended, and be grown on rapidly under the same conditions as described above.
The plants will this season make rapid strides, and be ready by the end of June or beginning of July to be transferred into 10-inch pots, provided every attention recommended has been carried out. They should be again kept close until they have taken to the new soil. As soon as the roots are working freely into the new compost, any shoots that require stopping should be attended to, and then grown on rapidly under the influence of plenty of light and sufficient air to cause their growth to be short, and possess that solidity which is requisite for a good set of flower-buds. A good set is certain - such as will well repay the cultivator for the sacrifice of the previous season's blooms.
This second potting in the year will not be necessary after the plants have attained a fair size and in 10-inch pots. Unless the object of the cultivator is to get them into a very large size as quickly as possible, 10 and 12 inch pots are large enough for all ordinary purposes. When transferred into the last-named size they can remain in them for several seasons, if supplied with a little manure-water while making their growth and swelling their flower-buds, at which season we think the feeding most necessary. Nothing is better than an occasional application of clear soot-water, which acts immediately on the plants, and imparts a beautiful glossy colour to the foliage. Plants can be kept in smaller pots under the same circumstances if deemed necessary.
The time of potting varies according to the time the plants are wanted to flower. Some cultivators prefer potting as soon as the blooming is over. We would recommend this operation to be carried out as soon as they commence to set their flower-buds. At this time they always unfold a quantity of leaves, and the roots are active and soon take to the new soil. The plants, after blooming, are ready to be cut well back, and will start at once into vigorous growth without being again disturbed.
In training the plants, the foundation must be begun early by bringing the shoots down to the rim of the pot, if nice round bushes are required, which can afterwards be easily kept in shape by stopping and regulating the shoots as they grow. When they have become large plants, they can be cut into shape with the knife after blooming. We cannot too strongly condemn the mode of tying and twisting the shoots of the plants into the form of pyramids and other shapes, looking as if they had been clipped into shape with a pair of shears, instead of using the knife at the proper season. We allude to this especially because the plants are so subject to all kinds of insects, and the great difficulty experienced in keeping the plants clean. If the growths are twisted and tied closely together, the plants do not show off their flowers so well, nor are they so natural-looking as if grown into nice round bushes, without either tie or stick, after the foundation of the plants has been formed.
A system we have found useful for growing plants suitable for small vases, etc, is to strike the cuttings in early spring in small pots, and then pot into 4-inch pots when rooted, keeping the plants well stopped and close to the glass on a shelf: by so doing the plants will be very dwarf and produce about four blooms each. Another system we have adopted with success - viz., striking four or five cuttings in a small, say 3-inch pot, as soon as growth is completed and it can be seen which shoots are going to bloom. Care must be taken that they do not again start into growth after taking root, until it is seen that the flower-buds are swelling; and then the growths, if they start before the blooms expand, are better picked off.
Wm. Bare-net. Norris Green.