Starting From Cuttings
Cuttings form of cheap and often easy method of reproducing a desired specimen: a certain tomato plant or favorite rose. However, the new plant is a clone of the first, is genetically identical, and shares the same weaknesses and strengths of the original plant. Thus, your rhubarb or rubber plant may be identical to your neighbours', and importantly, can be equally susceptible to the same problems.
Growing from cuttings is easiest for non-woody plants. Deciduous trees and shrubs are also fairly easy in spring; hardwoods and some ever-greens may prove difficult.
Most plants are reproducible in this manner, though some coaxing may be needed. Plants that have been pruned in the previous growing season produce the most vigorous shoots and are most likely to root well. Rooting hormone or willow extract can significantly aid with difficult plants: stand cuttings in willow extract for one or two days, then pot, or water with willow tea after potting. See relevant section.
Use only new growth from young specimens, if possible. Plants should ideally be pruned back the previous fall, so that the new, healthy and very vigorous stock may be used as material for cuttings. Use a sharp, clean knife. Keep cuttings moist and cool until ready to pot up, and ideally take these in the early morning, an hour or two after watering.
Softwood cuttings taken in the spring usually work best; plant immediately. Grow in good indirect light, temperatures of 60-80F/15-27C, and in a humid atmosphere: mist frequently, or enclose the pot in a plastic bag, allowing it to breathe several minutes daily. Bottom heat may help.
Semi-hard or semi-ripe cuttings are taken from mid-summer to early fall, and are harder to grow, but share the same requirements.
Hardwood cuttings are taken at the start of the dormant season, when leaves have dropped, and as such, humidity is less a priority. These are often overwintered in a cold frame, with new growth expected the next spring.
Grow cuttings in a rooting medium consisting of well-draining soil or peat mixed with sand, perlite or vermiculite. Peat mixtures especially will be sterile and protect against disease. Cuttings, especially if harder to root, may be tied into small bundles prior to planting. Protect, and watch for fungal infection.
Inspect regularly for growth, and pot up into small pots. Rooted specimens should resist a gentle tug; if not yet rooted, stick back into the medi-um. Remove and discard rotting specimens.
Some cuttings will even root in water (plant up if roots are 1" long), or reproduce by runners which may be rested onto fresh, moistened compost until the new plantlets grows roots, after which they are severed from the parent plant.
Stem Cuttings
To take stem cuttings, cut immediately below a leaf joint, some 3-4" down a young tip. For woody plants, select the joint where new and old wood meet. Ideally each cutting should have at least three nodes or stem divi-sions. Break off leaves from the lower 1/2 of the cutting, and leave an up-per 2 or 3 leaves. Dip in rooting compound if desired, then insert 2 to 3" into the rooting medium.
Non-woody plants often allow multiple stem cuttings to be taken, one below the next. Tip cuttings are the most vigorous, but these may not branch whereas lower cuttings, if used, are more likely to do so.
Cut on an angle to identify this as the lower part of the cutting (it points downward, into the growing medium). Use a straight transverse cut to identify the cutting's upper end. Use only upgrowing material: some cut-tings will try to maintain their initial direction of growth.
Large leaves left on a stem cutting can lead to unacceptable water loss,
and failure. Any such leaves should be cut back, or removed, though the average houseplant must have a few good leaves left on the cutting. Of course, growing in a covered pot or propagator can minimize water loss.
Hardwood cuttings are somewhat different: make the top cut just above a newly dormant node, late fall or early winter, and the lower cut some 6" down, just below a node. Dip in rooting hormone. If a single-stemmed tree is desired, plant with the top node just below soil level, otherwise, plant with third node at soil level. Plant in well-drained, protected soil, such as in a cold frame.
Coniferous cuttings are taken from young, vigorous growing tips, each with a small brown hardwood base. Remove the lower 1 1/2" of needles or leaves, dip in rooting hormone number three, and plant 1 1/2" deep.
Succulent cuttings should be several inches in length, and are left to root in air, or at least allowed a few hours, usually days, to callus. When pot-ted, water only sparingly, and keep in a drier atmosphere. Benign neglect is always a good policy. Do not take cuttings from the woody stems of succulents.
Heel Cuttings
Heel cuttings are treated much the same as stem cuttings, but are simply torn from a larger branch. This is the preferred technique for semi-hard materials, such as maturing new growth on trees and shrubs, in the summer, and for hardwood cuttings, taken in the fall. Use this technique also for new growth less than 4" in length.
Very thin cuttings are taken, i.e. no wider than 1/16". Trim the thin tail on the heel cutting, remove lower leaves, and plant up gently. Use a rooting hormone. Usually rooted without bottom heat.
Leaf Cuttings
Leaf cuttings are another effective method of reproducing some types of plants. Some cuttings are cut across the leaf, planted with the stalk side of the cutting facing down, into sterile compost. Others are planted with the stalk still attached, and yet other leaves may be cut into 1-2" squares and be potted up individually. The outer part of the leaf should always point up; use only freshly harvested, mature leaves for any type of leaf cutting.
Good levels of humidity are essential for these types of cuttings. Leaves loose moisture easily, and have no ready source for water; minimize tran-spiration losses by enclosing all such cuttings in humid environment. DO NOT allow to dry out. Warmth aids propagation; a soil temperature of 70F/21C is usually ideal. A sterilized or peat-based growth medium is essential.
The simplest leaf-stem cuttings involve cutting the stalk 2" below the leaf base, using a very sharp instrument. Plant with the leaf base even with the level of the soil, and bury leaf and stalk at an angle, shallowly.
Some leaves, i.e. of begonias, are simply laid flat on the soil, pinned down if needed, after making small nicks 1" apart across major veins. The old leaf will slowly fall apart as new plantlets take root.
Begonia leaves may also be cut into squares some 1" across, and buried vertically with the veins of the leaves pointing upward and outward, about 1/2" deep.
Transverse sections of lance-like leaves may be taken from certain species: the leaf is cut into sections 2-4" across and are potted with the central vein and one cut end pointing up, and the other completely buried.
Succulent leaves can often simply be broken from the stem, and kept warm and shady. Allow to wrinkle, wait for appearance of roots and very small new plantlets, often months. Then lay flat on soil in a small pot. Water lightly and infrequently, and ignore.
Root Cuttings
Some species, notably quite a few perennials, are very readily propagated by root cuttings. Though this may seem drastic, it is easy and well tolerated by many plants. Healthy stock should be used, lifted prior to the growing season, and washed free of soil. Select young healthy roots the size of a pencil for woody plants, smaller for non-woody ones, and cut straight across, just below the crown. Long roots may be cut into multiple sections.
As with stem cuttings, I use a transverse cut to mark the upper end of the cutting, the one closest to the crown, and an angled one pointing downward into the soil to identify the lower part of the cutting. Cuttings MUST be oriented correctly.
How cuttings are grown determines how long they should be: if rooted in a warm propagator, cuttings 2 to 3" long should be adequate; if rooted in a cold frame, make them 3 to 4" long, and for those left to overwinter in the cold, unprotected ground, 4" or longer is required.
Plant in loose, barely moist, well-drained soil in a cold frame, or simply pot up and bring indoors. Poke a hole into moist, well-draining medium with a pencil and gently lower the cutting until its top is even with the soil surface, one or two per pot. Cover with a thin layer of grit or fine gravel. Keep in a humid environment, and water very sparingly.
Note that stem and leaves often develop before the new root system, but that the new roots must appear before increasing with watering. Also, DO NOT use Rooting Hormone, as this actually has a detrimental effect.
Rhizome cuttings are treated in a similar manner, though each section should have at least one shoot; sections are planted horizontally, with the shoots pointing up. This technique works well for many diverse plants, from rhizomatous-rooted bamboo to hops, as well as numerous others.
