Plant Propagation (Continued)
Propagating with Cuttings
In botany, a cutting is a severed section from a plant’s root, stem, or leaf which can develop into a new plant. The cutting is first placed in water or a growing medium until it develops roots, and then the rooted cutting is replanted into pots or a garden.
A sharp knife or razor should be used to severe a cutting from a plant. Before taking each cutting, the knife or razor blade should be cleaned with isopropyl alcohol or a solution 9:1 ratio of water to bleach to prevent the transfer of diseases.
Once a cutting has been taken from a plant, all flowers and flower buds should be removed so that all its energy and stored carbohydrates can be focused on producing roots and shoots rather than focusing on fruit and seed production. For cuttings other than soft, fleshy stems, a rooting hormone can be used to speed up root production, produce more roots, and/or make the roots more uniform. It is preferable to use a rooting hormone containing a fungicide.
Rooting mediums should be sterile, low in fertility or soluble salts, and drain easily so roots can take in oxygen needed for respiration while at the same time retaining enough water that the cutting does not become stressed. The most common rooting mediums used are coarse sand, vermiculite, a blend of equal parts peat moss and vermiculite, or a blend of equal parts peat moss and perlite. The planting medium should be moistened before inserting cuttings and should be kept moist throughout the rooting and shoot formation process. The potted cuttings should be placed in a clear plastic bag closed with a twist tie or rubber band to retain moisture.
Stem and leaf cuttings should be placed in an area with bright indirect. Root cuttings, however, need to be exposed to sunlight to stimulate adventitious budding and shoot development. So, the end of the root cutting from the stem side of the root needs to be planted in such a way that it is exposed to direct sunlight.
How to Take Stem Cuttings
While many plants can have stem cuttings taken any time of the year, there are others that cannot. For example, stem cuttings from most evergreen woody plants should be take in fall or during their dormant season while stem cuttings from deciduous plants should generally be taken in late spring and summer. There are several ways in which stem cuttings can be taken.
Tip cuttings are names so because they are taken from the tips of stems. These cuttings are typically 2- to 6-inches in length and include the terminal bud. The cut should be made just below the bud. If applicable, dip in a rooting hormone solution and gently tap or shake the cutting to remove any excess solution. Use a pencil or stick to poke a hole in the rooting medium deep enough for the cutting to support itself. Making the hole slightly bigger than the cutting’s diameter should prevent the rooting hormone from being wiped away when you insert the cutting. Carefully insert the cutting into the hole and gently firm the soil around it. If you plan to insert multiple cuttings in a single pot, then space them so that their leaves do not touch.
Medial cuttings come from the interior of a stem rather than its tip and require two cuts on the stem: the first just above a node and the second just below a node 2- to 6-inches down the stem. These cuttings should be prepared and planted in the same way that tip cuttings are.
Cane cuttings are taken from cane-like stems which are cut into sections that contain one or two nodes. The ends of the nodes should be treated with fungicide or a dust containing activated charcoal before allowing it to dry several hours. Once dry, the can cutting should be laid down horizontally on top of the rooting medium and pressed into the medium so about half of the horizontal cutting is above the surface and half below. Once roots and new shoots begin to appear, cane cuttings are typically potted or planted in a garden though some may have their new shoots detached and rooted again.
Single Eye Cuttings
Single eye cuttings are taken from plants with alternating leaves when there is not a lot of space or stock material. The stem is cut about ½ inch above and ½ inch below the same node. Place the 1-inch stem cutting either horizontally or vertically in the rooting medium, making sure the axis where the leaf meets the node is just above or just touching the medium surface.
Double Eye Cuttings
Double eye cuttings are taken from plants with opposite leaves when there is not a lot of space or stock material. The cuts to the stem are made the same as with single eye cuttings (½ inch above and below the same node). The 1-inch stem cutting vertically in the rooting medium with the node just touching the medium surface.
Heel cuttings are made by carving out a section of woody stem around the axil where a leaf and axil bud is located. The cut is made in an arc or shield shape about halfway through the woody stem. These cuttings are placed in the rooting medium horizontally for propagation similar to the way cane cuttings can be rooted.
How to Take Leaf Cuttings
Leaf cuttings are used primarily to propagate plants with large leaves like a few types of house plants. It has limited uses because the leaves of most plants will simply decay or product roots but no shoots. There are four main methods of cutting leaves for propagation.
Whole Leaf Cuttings with Petiole
This method requires that you cut a leaf from the plant such that it still has ½ to 1 ½ inch of petiole. The lower end of the petiole where it would attach to a stem is then inserted into the rooting medium. One or more plantlets will form at the base of the petiole under the medium surface and can be removed from the leaf cutting once they have formed their own roots.
Whole Leaf Cuttings without Petiole
This method is used for sessile leaves, those leaves that have no petiole. The leaf is placed vertically in the rooting medium with the base of the leaf and its axillary bud just below the surface. Once the plant has developed roots, the leaf can be removed.
Split Vein Leaf Cuttings
This method requires that you remove a leaf from an existing plant and slit its larger veins on the bottom side of the leaf blade. Lay the leaf on the rooting medium with the bottom side of the leaf with the slits touching facing down towards the medium. Should the leaf start to curl up, place some rooting medium on top of the leaf blade along its margin to weigh it down. New plants should form at each slit in the veins on the underside of the leaf.
Leaf Section Cuttings
This method uses sections of leaves to propagate and is frequently used with snake plants and some fibrous rooted begonias. A single begonia leaf can be cut into wedges with each wedge containing a primary vein. The leaf wedges can then be laid flat on the rooting medium, and a new plant should arise from the vein. Snake plants can be cut into 2-inch cross-sections with the top cut being straight across the leaf while the bottom cut is slanted so that you can tell the top from the bottom. Because cuttings from succulents and other fleshy plants tend to rot if kept too moist, it is best to allow the cutting to dry for 12 to 24 hours before inserting them in the rooting medium. Once the cutting has been allowed to dry, insert it vertically with the slanted bottom of the cutting in the rooting medium.
How to Take Root Cuttings
Root cuttings are typically taken from mature plants 2 to 3 years old so that they have had time to develop an extensive root system. The cuttings are taken during their dormant seasons so the roots will contain a large supply of stored carbohydrates. Depending on the plant species, the root cuttings may develop shoots first and then their own roots or they may develop roots first before developing shoots.
Root Cuttings from Plants with Large Roots
When taking root cuttings from plants with large roots, be sure the top cut is straight across the root and the bottom cut is diagonally across the root so that you can tell the top from the bottom. Store the root cuttings in moist sawdust, peat moss, or sand at 40° F for about three weeks. After three weeks, insert the root cutting vertically with the slanted (bottom) end in the root medium and the straight cut (top) end about even with the rooting medium surface.
Root Cuttings from Plants with Small Roots
When taking root cuttings from plants with small roots, cut them into 1- to 2-inch sections. Bury the root cuttings horizontally about ½ inch below the surface of the rooting medium.