Root and Rhizome Cuttings
Sections of roots are sometimes cut to propagate house and greenhouse plants, but the practice is more common with hardy garden plants. But pieces of thickened, stemlike, or rootlike rhizomes can be taken from many types of indoor plants. Rhizomatous begonias, and rex begonias of rhizomatous habit, are familiar examples. Each piece of rhizome should have at least two, but preferably three, “eyes,” or scars from which leafstems have grown. The piece is placed half in and half out of the moist medium in the propagating box. Roots grow from the bottom down into the medium; stems and leaves shoot up from the eyes on top.
Layering
There are two general methods of layering, and in each case the plant is completely rooted before it is cut away from the parent. In “air layering” a thick stem, or cane, is slit, wrapped with moist sphagnum moss, and enclosed in plastic until roots are produced. This method is usually practiced on large, overgrown plants such as dieffenbachias, and truthfully is not necessary, or practical, for most miniatures.
But ground layering is a safe and sure way to propagate almost any plant with lax stems, and is particularly useful on temperamental plants such as some miniature ivies, which are reluctant to strike roots on stem cuttings. It is very simple. Just pin down the stem, not too far from the growing tip, in the soil beside the mature plant. If you like, you can put it in a pot of its own and thus be one jump ahead by having the roots where you want them. I usually steal a hairpin out of my “bun,” but a section of wire bent into a U will do. When the stem has rooted, cut it off on the side next to the parent plant. Unless it is already rooted in a pot, dig it out and plant it.
Division of Crowns and Roots
One African-violet plant may grow several crowns, or main stems complete with rosettes. Since single-crown plants usually are more shapely and bloom more abundantly, the extra crowns can be cut off and rooted like ordinary stem cuttings. This is one of the more popular methods of dividing an old plant and getting several new ones from it.
Some plants will eventually make such dense, bushy growth that they not only look obese and unattractive, but are prey to all sorts of rot. Root division not only gives these plants a new lease on life, but also provides several new plants. Remove the overgrown plant from its pot, and very gently, try to split the matted roots and stems into separate sections. Do this with your fingers and not a metal instrument. If you work slowly and with care, several will most likely pull free. If you can’t do it with your fingers, you may have to resort to a clean sharp knife, in which case cut down past the stems and through the roots, making several separate sections. Discard any damaged leaves. Pot up the divisions, and keep them shaded and protected for a week or so until they recover from the shock.
Runners, Stolons, and Offsets
Many plants are continually propagating themselves by producing new plants in clusters around the old ones, sometimes at the ends of underground stolons or above-ground runners. Saxifraga sarmentosa was named “Strawberry begonia” because it continually produces new plants on runners, strawberry-style. Episcias and chlorophytums are other examples.