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.
THERE are few plants which interest ordinary observers more than these, when well grown; and like Orchids among flowering plants, they, when bearing well-developed pitchers, give a superior tone to the collection of foliage plants with which they may be associated.
Some of the new or rare kinds are rather expensive, but small plants of many good kinds may be obtained at a moderate price, and will not fail to interest both cultivators and visitors. There has been a good deal of misunderstanding with regard to the foliaceous organs of Nepenthes and their remarkable pitcher-like terminations; but it is now generally acknowledged that the ascidia or pitchers are merely appendages developed from a gland which terminates the prolonged nudrile of the true leaves, and not a modification of the petioles with the true leaf for the lid, as was formerly supposed. The flowers are borne on erect spikes, and are generally of a chocolate colour, not very showy. The male and female flowers are borne on separate spikes; and as it rarely happens that male and female flowers are produced at the same time, unless it be in large collections, it follows that they are not so frequently hybridised as they otherwise would be. This is a difficulty often experienced by the hybridiser, not only in this but in many other classes of plants bearing dioecious flowers; but many kinds of pollen will retain its fertilising power for months after the flowers are produced, if it be carefully collected when matured and wrapped up in tinfoil.
I have frequently preserved pollen for a long time by collecting it when dry and placing it in short lengths of common glass tubing. After a sufficient quantity has been introduced into the tube, the ends may be hermetically closed by having a flame from a candle or gas-jet blown steadily on them, after which they can be duly labelled and laid by until wanted. These tubes must not be broken too short, or the pollen might be neutralised by the heat from the jet.
Nepenthes are very easily propagated from cuttings taken off when the plants are in full growth. These may be taken from the sides when borne in that way, or the tops of tall plants may be taken off with three or four leaves each, and inserted in a layer of fresh living sphagnum. A close case, with bottom-heat ranging from 60° to 90°, is most favourable to the emission of their exceedingly delicate, black, hair-like roots.
Nepenthes will also root freely during summer if the cuttings are inserted in clean-washed gravel or Derbyshire spar. When the cuttings are well rooted, they must be carefully removed from the moss or spar, and placed in either pots or baskets, the latter being preferable in most cases for small plants. These plants require a sweet and very open or porous compost, with ample drainage; for although they are partial to an abundant supply of water at the root, when in a well-established and growing condition, still the least approach to anything like stagnant moisture is extremely injurious to them, and will soon ruin the most promising specimen. A good compost for these plants, and one which I have found by experience to answer its purpose admirably, is composed of fibrous peat, the smaller portions being removed, and one-third of fresh chopped sphagnum added. To this add coarse white sand, and a little leaf-mould. After the plant is placed in the basket or pan, a layer of living sphagnum may be added, and will greatly improve the appearance of the plant. I find that the roots of Nepenthes ramify very freely in living sphagnum moss, just as those of Orchids do under similar circumstances.
A few well-grown plants add greatly to the appearance of an ordinary plant, stove, or East Indian house, and the temperature and humidity of the latter are just the conditions required for their development. The plants must be shaded from bright sunshine, more particularly until they are thoroughly established, after which they may be gradually inured to more sunlight, by which treatment the colouring of the pitchers is most beautifully brought out. The amount of shading requisite depends mainly on the aspect of the house in which they are grown. If the house is a lean-to, and has a northern aspect, a minimum quantity will be required; while, if it faces the south, the glare during the middle of the day will often be intense, and more shading will be required in consequence.
Fine specimens of different species of Nepenthes are grown at Chats-worth, trained up the front of the Amherstia house. These are but moderately shaded, and bear fine highly-coloured pitchers in abundance. During a visit I paid to that princely establishment two years ago, I found Mr Speed had dozens of cuttings that had been struck in the spar and gravel with which the side benches of that interesting house, devoted mainly to the Amherstia nobilis, are covered. In one of the Orchid-houses was one of the finest-grown specimens of N. Hookerii ever seen, a perfect picture of luxuriant health and sturdy vigour. This plant was as elegant as a well-grown Draccena Cooperii, and its fresh- green leaves were each terminated by a large heavily-blotched pitcher, reminding one of some strangely fantastic tropical fruit.
Several interesting hybrid Nepenthes have been raised from seed by Messrs James Veitch & Sons of Chelsea, who possess one of the most magnificent collections of these plants to be found in this country; and it is a rich treat to walk through their Nepenthes house and inspect the fantastic urn-like appendages that droop in such rich profusion both overhead and on all sides. The seeds of Nepenthes remind one of dry old larch-leaves in shape and colour, and are produced in immense quantities in the jungles of Borneo, Sumatra, and other islands of the Indian Archipelago, where these plants mostly luxuriate in the jungles, forming in some places a dense thicket or mass of undergrowth. Several very remarkable species, which have been fully described and beautifully illustrated by Dr J. D. Hooker, C.B., from dried specimens preserved at Kew, still remain to be introduced to our collections by some enthusiastic and enterprising traveller in Borneo. These include N. Rajah, N. Edwardsiana, and N. Lowii, the former bearing pitchers quite a foot long, and fully six inches in diameter.
This species is spoken of by travellers as bearing pitchers capable of holding several pints of water.
Another interesting feature connected with Nepenthes, and indeed with both American (Sarracenia) and Californian (Darlingtonia) pitcher-plants, is the propensity for attracting flies into the urn-like appendages, from which they rarely escape. If old dead pitchers are examined either at home or abroad, they are generally found to contain dead flies, and occasionally other insects. Some writers affirm that the flies are dissolved in the glutinous liquid distilled by the pitchers when young, and that they are thus absorbed and enter into the economy of the plant; but this requires further investigation, since no distinct facts have been noted to prove this assertion. The slightly glutinous water contained in the younger pitchers is perfectly wholesome previous to its becoming polluted by the insects, which invariably accumulate and putrefy therein soon after the lid of the pitcher opens.
In the following papers we shall give a descriptive list of most species of Nepenthes at present cultivated in our gardens, as well as hints on the culture of Sarracenia, Darlingtonia, and Cephalotus, also commonly known in gardens as "Pitcher-Plants," though essentially distinct from the true Pitcher-Plants, or Nepenthes. F. W. B.