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.
We propose giving the details of our mode of cultivating this beautiful Orchid, for we have been singularly successful in its cultivation; and as it is very seldom seen in robust health, or producing the quality or the quantity of flowers of which it is capable, we think we cannot do better than tell everything we know connected with the cultivation of this much-written-about, much-appreciated Dendrobium.
To give minute details on the subjects taken up by nearly all horticultural writers, is such a rare thing, that we feel we ought to apologise for so doing in this particular instance. And yet those papers which do so are of most value. We expect to find principles and general directions only in such volumes as those written by B. S. Williams, F. W. Burbidge, and many others; for it is impossible to describe every particular in octavo volumes of two or three hundred pages : and indeed such would be out of place. In weekly or monthly magazines we expect more; and those who write for such, and yet fail to give more, merely repeat what has been often better said before. Why this should be, we do not understand. Possibly some writers think details below them, or, understanding what they write about themselves, think that all small matters ought to be known by their readers - although only the vaguest hints are given, and these often by no means plainly put.
The plagiarism of horticultural writers is being continually talked about; but the evil does not abate. Few, indeed, imagine themselves plagiarists, even when recasting what has been recast and re-repeated hundreds of times for a generation or two. Surely there is enough original experience to fill all our papers, if only writers would condescend to tell us the little almost-nothings which yet make up the sum-total of our everyday practice. We are told that drops make the ocean, and grains of sand the mountain : just so in the case of horticultural practice. Those who succeed attend to every little, and it is by neglecting the littles that others fail. Those who essay to teach should tell us all about the little steps, slips, jumps, by which they have climbed the mountain called Difficulty. The ordinary readers who get their horticultural knowledge from books and papers, too frequently attempt success by bounding from stage to stage, instead of feeling their way step by step.
We hope the above will be taken partly as a broad hint to gardening scribes, partly as an apology for details which may to adepts seem whimsical and superfluous.
But to return to our subject. When flowers are wanted from plants of Dendrobium nobile at once, or within a year, flowering-plants must be secured for commencing with. If telling success be the aim of the cultivator, healthy, one-year-old, just-as-they-are-going-to-start, young growths from off the base of old ones are to be preferred; at least we prefer these - and we have tried two or three ways of getting up a stock rapidly. If anybody knows a better way, they may be sure one cultivator, at least, will be glad to hear of it.
However, having mentioned flowering-plants first, we will say something on how to treat these best. When they are grown in an ordinary stove or house of similar temperature, they will be pushing new shoots and new roots by the beginning or middle of February. At this stage they should be repotted. The first thing to do is to carefully pull off any young stems which may be growing near the tops of old ones, and to pot them off on their own account in the manner to be afterwards described. Do not begin these operations until growth is apparent - although orthodox growers all advise this course. From John Bull to John Chinaman the nightmare of orthodoxy hangs about the necks of men like a millstone, and encumbers their progress like a Sindbad! The orthodox time of potting Dendrobium nobile certainly stands in the way of success. The orthodox mixture of moss, peat, crock, charcoal, and sand, is another hindrance - inherited, like other evils, from pur fathers. They first potted the plant in ordinary soil; that rotted the roots and killed the plant. Some thinking person broke away from this and used the above mixture with a good deal of success. We ask you to discard this practice also, and to use only living sphagnum moss and charcoal.
You may object that there is no nourishment in either of these articles. Never mind; they are better alone than with any other substance added or substituted.
In potting, turn the plants out of the pots carefully, so that neither root nor pushing growth be injured. Carefully pick away every particle of the old potting material, and cut away all decaying roots. Wash the remainder until perfectly clean in the water-tank, and then lay them aside, - they are ready for potting. Pot them into clean, dry pots, of a size that will just allow the roots to be comfortably accommodated. (Pots large enough to hold a quantity of material which is never taken possession of by the roots, is an unmitigated evil in Orchid cultivation. They do far better when the roots are crowded - not too much - in the pots). Fill the pots just about half full of fresh charcoal; put a thin layer of fresh sphagnum on the charcoal, and then distribute the roots carefully and evenly in the pot; afterwards work in an equal quantity of sphagnum and charcoal among the roots, and make it moderately firm. Some Orchids require firm potting, others are better loosely potted: this one thrives best in a compost moderately firm. It is a good plan, especially for careless waterers, to have the base of the plants a good deal higher than the rim of the pot; and we also advise pieces of charcoal to be placed underneath the bases of the bulbs.
Over all a layer of fresh growing sphagnum should be placed; but care should be taken not to put it over the base of the bulbs, for that will cause them to break half an inch or so up the stems; and growths which do not start from the very base are not worth having.
After the plants are nicely potted they must be put into the stove, although a vinery - especially where Muscats are grown - will suit them. A warm moist atmosphere they must have while growing. At first the material must be kept only moist and no more; and a thorough watering once a-week in a moist house will be sufficient to secure this. To keep the surface-moss fresh, and to encourage it to grow, a slight damping with the syringe once a-day will be necessary; and growing moss is of some importance, for if it dies and gets covered with slimy matter, the roots as they descend from the base of the bulbs, instead of penetrating it healthily, will rot and die, and your bulbs will be weak and annually weaker, instead of strong and annually stronger.
All through the summer the plants should have stove-heat, and be shaded during the hottest part of the day. until their bulbs are nearly made up. They should then be removed to a warm place - such as a Melon or Cucumber pit - and treated to a dry, airy, warm atmosphere, and be exposed to the full blaze of the sun. At this stage, just as much water as will prevent their shrivelling, and not a drop more, should be given. They ought to go days and days without a drop. Six or eight weeks of this treatment will turn the bulbs hard and amber-coloured, and the plants will go to rest. They should have a couple of months' rest, in a temperature not much under 50° nor over 55°. When wanted to flower they should be treated to stove-heat. By forwarding the plants a little each year, a batch may be timed to flower at Christmas; and by retarding others they may be had all through the early months of the year. We have seen them as late as June, but in this case they are so late in making their annual growth that it cannot be ripened properly for want of sun - at least north here; and consequently they do not flower well the following year. When a young stock is being continually raised, only worn-out plants should be kept for very late work, and then, when flowering is over, thrown away.
Thrip (yellow), red-spider, and mealy-bug all thrive on Dendrobium nobile. The two former are easily kept down by the syringe. The last needs picking out with a sharp-pointed stick.
And now for the best way of getting into a stock. It requires a few years of patient good treatment, but the results will justify the waiting and the work. We have said what beginnings are best. Given one, or one hundred, - it is all the same - year old stems, of the length of one's finger and upwards, such as we described before, they should be cut carefully from the parent stems so as to injure neither. Take care of the whorl of roots at the base. When the buds at the base begin to push and the roots to grow, pot them up singly into 3-inch pots, among a compost of roughly bruised fresh charcoal and the freshest sphagnum procurable. One crock over the hole in the pot will be sufficient for drainage - the whole material will be open enough for drainage, for it will speedily become one mass of roots. "Half-and-half " is the proportion to employ of each. Into this the shoots are not to be embedded, but the plants should rather stand on "tiptoe" on their own roots. The base of the young bulbs should just touch the moss - which should be kept slightly moist and growing, and no more.
Kept in stove-heat and carefully treated, these plants will soon fill their pots with roots, when they should be treated to pots one size larger.
Instead of ripening off these small plants in the way advised for flowering-plants, they must be retained in the stove, or East Indian Orchid house, where such exists, and kept growing. Treated thus, they will make from two to three growths a year instead of one, and will double their number of breaks every time. Continual growing, and continual shifting on as this becomes necessary for four years, should produce plants a yard across, from 2 to 3 feet high, and with from twenty to thirty leading bulbs.
Such treatment produces rude health and rank growth but no flowers; and some little skill may be necessary to throw them into a flowering state, for when in this robust condition they are generally breaking at the base before the preceding bulbs are half grown. This habit has got to be changed. To do this, water should be sparingly given long before the growths are completed. Even with this stinting they will break again at the end of summer, and if these new breaks are allowed to grow, your purpose will be frustrated. Allow them to grow 6 inches, and then pinch them. At the same time ripen the bulbs off in the way before mentioned. In spring you will find that the pinched stumps will break grandly, and the plants produce such a crop of flowers, on two or three sets of bulbs, as will be a reward for time and labour.
The time at which the flowers are wanted must regulate the time when they are to be removed from the place where they are resting to a warm house; but this plant is very patient in this matter, and a few weeks longer or shorter of a rest will not harm it much. However, after it has once begun to grow, it must have a continuous growing temperature until its bulbs are again made up. While in flower the plants may be put into a house considerably cooler than a stove, but it is not wise to subject them to greenhouse treatment. A. H., H.