This section is from the book "The Gardener V3", 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.
The merits of this family are so well known, as represented by the many varieties of the late-flowering and the early-flowering sections now in cultivation, that it is quite unnecessary to do more than allude to these. The huge pyramidal heads of bloom borne by the finer kinds of the late-flowering section, in addition to the rich colours of some sorts, has somewhat eclipsed the neater growing early-flowering sorts, notwithstanding the fragrance and waxiness of their flowers as compared with the more popular section. Unfortunately, from a florist's point of view, the Phlox is much too easy to cultivate. The flower-ioving portion of the community, as a matter of course, look on that as a point in their favour; and, accordingly, allow Phloxes, when they get them, pretty well to follow their own devices, and, permitting them to grow into huge herbaceous masses, they cull the diminished heads of bloom, and think them lovely.
Such an easily accommodated plant may, in consequence thereof, be successfully cultivated without following rigidly any hard and fast line of culture. The cottager may gain his end for securing strong young growths by dividing his old plants quite as effectually as the most particular of particular florists, who only condescends to grow plants which are propagated at a certain season and in a certain way. Propagation by division is the simplest method of rearing young flowering-plants, and though in disfavour amongst those who cultivate the Phlox for purposes of exhibition, it is, nevertheless, when gone about at a proper time and in a proper manner, a very efficient mode of keeping up young stock. The best time to propagatate by division is about the end of September, - no earlier, and not much later. It is assumed that no plants older than three years at most are tolerated. Such plants may be broken into pieces just large enough to produce from three to five strong shoots the following season.
The ground intended for their reception having been trenched two or three spits in depth, and manured according to the wants of the soil or the size of the manure-heap, the divided pieces are to be planted about the same depth as before, and staked as the operation is proceeded with, in order to keep the old stems and foliage fresh as long as possible, to secure a grip of the soil to the young plants, and to mature the buds for a strong start in spring. These will break away early without suffering any check to the young shoots, and merely require to have the ground between the plants pointed when growth has fairly commenced; at the same time breaking off all the weakest sprays, the strongest of the shoots being selected to make the current season's plant. Five of these are quite enough to leave, that good heads of bloom may be secured. Other necessary work consists in putting strong sticks to each shoot at an early stage of their growth, mulching the surface of the beds with rotted manure where the soil is naturally poor and light: artificial manure mixed with soot, or by itself, and applied occasionally in showery weather, is very beneficial. Plants treated thus will produce very fine spikes. Plants for producing spikes for exhibition are propagated from cuttings.
These may be successfully struck at any season of the year. Small healthy root-cuttings make the strongest plants, and may be successfully struck with about equally good results in the long-run, either from the young growths produced out-of-doors in spring,, or earlier in the year from cuttings produced from potted plants kept over the winter in a cool house. In the former case the cuttings will strike in a cold frame, and may either (after roots are produced) be planted out in nursery beds, or potted and grown on for producing flowers in pots the succeeding year, after which the same treatment, when planted out in beds, will be required as above indicated for divided plants. In the latter case it is necessary to lift plants in autumn after the stems are cut down, and pot them up in as small pots as will conveniently hold the roots without breaking off too many of these to gain that end. These plants must be wintered in a structure where they will commence to move into growth shortly after the turn of the year, so as to have cuttings ready by the beginning of February. These cuttings are to be broken off at their junction with the root-stock, and inserted in an open compost in thumb-pots. There is no better place for putting these than a common dung-frame, a very useful institution at that season.
Here, with a moderately brisk bottom-heat, roots are produced in a comparatively short time. Air will be constantly required to be left on the frame, in order to keep the atmospheric temperature low, so that the young plants may have no inducement to commence weakly growth. When rooted, the pots are better taken out of the plunging material, on the surface of which they may stand for a week or ten days, when a shift into 4-inch pots will be necessary. A compost of loam and mushroom-dung is very suitable for these, a sprinkling of crushed bones being an advantageous addition. When potted, do not return them to the dung-frame, unless the heat has become spent and low. A cold pit or frame without means of artificial heating suits the plants admirably. There, as the natural heat increases,, the plants will grow slowly but healthily, at the same time filling the pots with strong roots. By the beginning of April another shift into 6-inch pots will be required. In these the plants will produce each, a strong spike; though rather late, the early-flowering sorts will flower at the same time with the established plants of the late-flowering section; and this is therefore a good way to get the finest of these in for showing at the autumn exhibitions.
The late-flowering sorts are useful for decorating the conservatory late in autumn. The succeeding year the same plants may be grown on still in pots, shifting them finally into 9-inch pots, and bringing on three to five shoots for flowering. These make handsome objects where the conservatory is a large one. Or the plants may be kept over winter in the pots, and early the succeeding spring planted out into beds prepared as previously advised for divided pieces. Spikes cut for exhibition very generally flag or droop shortly after staging. To obviate this to as great a degree as psssible, insert as much of the stem, with leaves attached, as at all convenient in water. By this means an infinitely greater amount of water is absorbed then when the end of the stem merely is inserted in the water. Some of the finer kinds for exhibition, as well as for ordinary decorative purposes, in both sections, are the following: Bryan Wynne, Lothair, Chanzy, Amabilis, Coccinea, Queen of Whites, Venus, Mrs Laing, Miss Macrae, Lady Napier, Duchess of Athole, Lilacina, A. M'Keith, M. Dunn, Princess Louise, Roi des Roses, Vierge Marie, Madame Moisset, Resplendens Coccinea. These are all strong-growing and fine varieties, and will form the nucleus of a collection to any one who wishes to "go in" for the culture of the Phlox.
R. P. Brotherston.