This section is from the book "Indoor Gardening", by Eben E. Rexford. Also available from Amazon: Indoor Gardening.
MOST plants adapted to cultivation in the house are propagated by cuttings, by division of the root, or by seed.
Comparatively few, however, are grown as seedlings, as plants from seed can not be depended on to "come true," to use a gardener's term-in other words, to reproduce all the peculiarities of the parent plant.
Probably nine plants out of ten are grown from cuttings. Nearly all plants adapt themselves to this method of propagation.
There are many complaints of failure in rooting cuttings. These failures are nearly always due to one of three things:
1 The cuttings may not be in the right condition.
2 The soil in which they are placed to root may not be of a character calculated to encourage the production of roots.
3 Proper care may not be given.
It requires considerable experience to enable the amateur gardener to decide when the branch of a plant is in just the right condition to make a cutting. It should not be soft and pulpy from recent growth. It should not be so old as to have a hard, tough bark. Writers on this subject tell us that half-ripened wood should be used, meaning by that a branch that is neither young or old- in other words, one in an intermediate stage of development. It is not an easy matter to tell when this half-way stage of development has been reached, by the looks of the branch. But if it is given a sharp bend, it will, in the majority of cases, if at the right stage to make a cutting, partially break, but some of its fibers will be elastic enough to stand the strain without breaking. This rule, if rule it can be called, does not apply to all plants, for some have stalks of such a brittle nature, in all periods of development, that they snap readily under ever so slight a bend. These must be judged by a feeling of hardness which indicates maturity.
Immature wood often decays before it has had time to form the callus necessary to the development of roots, while over-ripe seems unable to form such a callus. But when the cutting is in proper condition it will generally form roots in a week or ten days, according to the nature of the plant, if all other conditions are favorable.
Cuttings should be about three inches long. All but the two upper leaves should be cut off close to the stalk. These leaves should be left to keep up the circulation in the branch, until roots form. While cuttings will root in almost any kind of soil, I prefer the sand-method to all others. Any shallow box or pan will answer your purpose. Put about two inches of clean, sharp sand in it, and apply water enough to make it moist all through- really wet,-but not so much so that water will stand at the bottom. Insert your cuttings in the sand at least half their length. Pinch it firmly about their base. This is all it will be necessary to do, so far as planting is concerned, but constant attention must be given until roots have formed. Care must be taken to keep the sand as evenly moist as possible. If you neglect to apply water until the sand becomes dry, the probabilities are that your cuttings are ruined. Therefore look to the cut-ting-box or pan several times a day, and be sure that it never lacks moisture.
Some plants-like Geraniums and Fuchsias -form roots so readily that cuttings made from them will begin to grow in less than a week from the time they are put into the cutting-box.
Do not be in too great a hurry to remove the rooted cuttings from the sand. Let them get well started to growing before this is done. Then work carefully, for their roots will be extremely delicate, and a little hurried or careless work at this period may spoil everything.
Have the pots into which the young plants are to be put all ready for them, with a hole in the soil to receive them. Then cut about them, in the sand, and lift them out without breaking the soil if possible. This is best done by running a broad-bladed knife under the block of sand in which the young plant stands. Drop it, sand and all, in a hole made in the soil in the pot, and then press the latter firmly about it. Apply a small quantity of water, and put the newly potted plant in a shady place, and leave it there until it has adjusted itself to the new order of things. This it will speedily do.
I have seen some amateurs remove their cuttings from the sand by pulling them up, thus exposing their tender roots, and often breaking many of them. Never do this. You can hardly be too careful in handling them.
Cuttings of such plants as have a firm, tough bark, like the Oleander, Lemon, and Ivy, are often rooted in water. A large-mouthed bottle is suspended in a sunny place, and about half filled with water. Into this the cuttings are dropped, and allowed to remain until roots form. More water should be added from time to time as evaporation takes place. Frequently it will be weeks before roots show themselves at the base of the cuttings, but as long as the leaves at the top of the cutting remain fresh there is no cause for discouragement. Hard-wooded plants never form roots as readily as those of a softer character.
Plants which throw up several stalks from a sort of crown can be increased by division of the root. Each piece of root with an "eye," or growing point, attached will make a new plant.
The Calla, Vallotta, Amaryllis, and all plants of bulbous nature can be propagated by means of the little offsets that form about the old roots.
Layering is sometimes resorted to with plants of a hard-wooded nature that fail to root under ordinary treatment. Select a shoot sent out from the base of the plant, if possible. About six inches from its junction with the parent plant make a slanting cut halfway through it, from below. Then bend the shoot down in such a manner that it can be inserted, at the place where the cut was made, in the soil close to the rim of the pot. Make it firm and fast by pegs or pins, tying the end of it to a stick, in an upright position. A callus will generally form at the point where the cut was made, and from this, in time, roots will be sent out. While roots are forming the shoot will be receiving sustenance from the parent plant, as the cut made in it will only partially shut off the supply. Do not sever the connection between the shoot and the old plant until you are sure it has roots of its own. This you can determine by an examination of the soil at the place where the cut in the shoot was made.
 
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