Propagation Using Cuttings
Softwood
This is the most immature part of the stem. When using this for propagation, it is also the most difficult of all cuttings to keep alive. However, it has the highest capacity of all types of stems to produce roots. The younger and more immature the stem, the greater it’s ability to produce roots and propagate successfully.
Soft stem growth is produced continuously at the growing tip of any stem. The faster the growth, the more stem without wood will be present. As the stem matures, the growth will slow and the stem gradually hardens and becomes woody.
Softwood cuttings are best taken in the spring when new growth is at its maximum. These cuttings will have the greatest potential for rooting. Cuttings taken later in the season, usually after the beginning of June will be slower growing and have more wood present. These are referred to as green wood cuttings.
These cuttings are extremely susceptible to water loss which provides a challenge when taking and using these cuttings. The immature leaves have no mechanism for reducing water loss as is present in more mature leaves. If these cuttings wilt, the capacity for root production is lost. What is necessary is to take the cuttings early in the morning and immediately place the entire cutting in a bucket of room temperature water. Fill the bucket the day prior to allow the chlorine to evaporate and place in a shaded location. When taking the cuttings, keep the bucket out of the sun as much as possible. No sense in par-boiling the cuttings. Here are some recommended steps to follow:
1. Hard prune the desired plants in the winter to promote fast stem growth with a high capacity to produce roots.
2. It’s spring so time to get everything ready. Fill the bucket(s) with water and fill containers with rooting compost. My mix is 1/3 coarse, sharp sand (washed), 1/3 peat moss, and 1/3 perlite (the small stuff). Make sure the mixture is moist but not soggy. Fill the containers and firm to within 3/8 inch of the rim.
3. Time to take the cuttings. For best results, the cutting should be approximately 4 inches in length. Using a sharp pair of pruners or scissors, cut the base of the stem 1/8 inch below a leaf joint.
4. Place immediately in the bucket of water in the shade. Continue this process until all the cuttings are taken.
5. Assemble the rooting containers, a sharp pencil, and rooting hormone. Pick a shaded place to process and plant your cuttings.
6. Remove the leaves from the lower third of the cutting. Using scissors, cut the remaining leaves back by one-half.
7. Dip the cutting in the rooting hormone. Make a hole with the pencil in the compost. Insert the cutting up to its leaves and gently firm the soil around it with your fingers. Continue this for the rest of the cuttings.
8. When the container is full, gently water from above and place in a well-lit protected area. This protected area should be a polyethylene tent that will retain moisture in the environment and, therefore, within the cuttings.
9. To maintain moisture in the cutting compost, gently mist the cuttings once a day. Spray the cuttings with a dilute solution of liquid fungicide at least once a week.
10. When the cuttings have rooted, usually in three to six weeks, harden them off gradually over a period of at least one week. This is done by gradually reducing the misting and opening up the polyethylene tent for a longer period of time each day.
11. Once the cuttings have been hardened off, transplant to their individual containers. Place in a sheltered area and continue to grow until ready for transplanting to their final location or container.
Greenwood
The essential difference between softwood and greenwood cuttings is their speed of growth. As noted earlier, greenwood cuttings are taken at the beginning of June when growth has slowed. They do, however, require the same environmental conditions of moisture, light, and warmth as softwood cuttings.
Use greenwood cuttings to propagate trees and shrubs and the majority of herbaceous plants, such as chrysanthemums. Use the above steps with the following exceptions:
1. Prior to planting in the rooting container, trim the leaves from the bottom half of the cutting. Again, trim the remaining leaves by one-half.
2. Rooting of greenwood cuttings usually takes from three to eight weeks, so be patient. After rooting, treat the cuttings as above.
Semiripe Wood
During the late summer, stem growth slows considerably and the stems become harder. Cuttings taken at this time are called semiripe cuttings. As they are thicker and harder than softwood and greenwood cuttings, they have greater capability of survival. They are, however, subject to the same water loss problems. Due to their higher levels of stored food, they can survive and produce roots even in poor light.
1. To begin this process, prune the parent plant at the start of the dormant season. This results in strong, fast-grown stems for use in propagation the following season. These will have a greater ability to produce roots than cuttings taken from unpruned stems.
2. Now that it is late summer, fill the desired number of containers with your rooting compost. Use a mix of 1/3 coarse, sharp sand (washed), 1/3 peat moss, and 1/3 perlite (the small stuff). Make sure the mixture is moist but not soggy. Fill the containers and firm to within 1-1/2 inch of the rim. Add a 1 inch layer of fine (builder’s) sand, washed and firm.
3. Take the semiripe cuttings from a main stem with all the current season’s growth. If the stem has branched, remove the side-branches.
4. Remove the tip of the stem if it is soft, but leave it if the apical bud has set and growth has stopped for the year. Shorten the cutting to 4 to 6 inches long. Remove the lower leaves so that about 2 inches of stem is clear at the base. The remaining leaves should be cut back by one-third. Treat the cut at the base of the stem with a rooting hormone powder.
5. Make a hole in the sand layer with a pointed pencil or dowel about 1-1/2 inch deep so the base of the cutting enters the rooting compost below. Space the cuttings as close as possible, most likely 1-1/2 to 2 inches apart. This will allow the plants to shade each other and maintain a higher humidity in the leaf area.
6. Water the cuttings with a dilute fungicidal solution. This also helps to firm the sand around the cuttings. Place the containers in a polyethylene tent to help retain moisture and provide a high humidity level. My idea of a polyethylene tent is a one gallon food storage bag placed over the container with 3 to 4 long bamboo skewers in the container to keep the bag off the tops of the cuttings. Secure the bag to the container with a rubber band around the container top. Place the container(s) next to a window with bright, indirect light.
7. Check the containers periodically and water sufficiently to rewet the sand/rooting compost should the containers become dry. Remove all fallen leaves to prevent any disease/fungus build-up.
8. Rooting may start fairly rapidly or may wait until late winter or spring. In either case, leave the cuttings in the containers for the following growing season. Feed them on a regular basis with a liquid fertilizer and water when dry. Once the danger of any late frost has passed, the containers can be moved outside and the polyethylene tent removed. If placing them outside, put them in an area that receives filtered sun only.
9. After leaf fall in the autumn, the cuttings may be transplanted to the garden.
Hardwood
This is among the easiest techniques for vegetative propagation of plants. The hardwood cutting(s) are made during the dormant season from fully mature stems. Because the stem has no leaves, for deciduous plants, or is in a dormant state, for evergreens, the amount of environmental control required for successful propagation is minimal.
As with all methods of propagation, the single most important factor is to rigorously prune the parent plant the year before the cuttings are to be taken. This will produce stems with the greatest capability of producing roots.
Stems grow at various rates during the growing season with the greatest growth rate at the start. Even by the end of the season, the base of the growth that was produced has the greatest capability of producing roots and should be used for most hardwood cuttings.
Hardwood cuttings can be taken at any time during the dormant season but have the greatest potential for root development when taken at leaf fall or just before the buds break in the spring. Cuttings taken just before bud break will need a protected environment such as a cold frame and timed very carefully to avoid leaf development prior to root formation. This will lead to excessive water loss and death of the cuttings. With the above said, let’s start the process:
1. Prune the parent plant rigorously during the dormant season. Allow to grow without pruning during the next year.
2. In early autumn, gently run your hand down one of the stems you will use for propagation. If the leaves fall off, the stem is ready for use as a cutting. Plants form a corky abscission layer to isolate the leaf from the stem. This is the plant’s ‘leaf fall’. Most leaves, however, don’t fall off until helped by wind or rain. Don’t wait until this happens, do the hand test.
3. Hardwood cuttings may be up to 14 inches in length but 6 inches is usually more successful. Keep in mind also that hardwood cuttings are still susceptible to water loss. Don’t let them dry out in the propagation process.
4. Cut the stem(s) with all the current year’s growth flush with the parent stem. Make a sloping cut about 3/16 inch above the proposed top bud. Make a horizontal cut exactly 6 inches below the top bud. Ignore any buds below the top bud when making this cut.
5. Treat only the cut base with rooting hormone and not the stem.
6. Bundle the cuttings into desired quantities (6 to 10) and place them into a sandbox, almost to their full depth. The sandbox should contain coarse, sharp sand that has been thoroughly washed. Leave the cuttings in the sandbox for the duration of the dormant season.
7. Just before bud break, prepare the planting area thoroughly by incorporating a mixture of 50% compost and 50% peat moss. Dig a furrow 5 inches deep. Place the cuttings vertically in the furrow at 4 to 6-inch intervals. Firm back the soil leaving about 1 inch of the cutting exposed.
8. Irrigate and fertilize the cuttings throughout the growing season. In the fall, after leaf drop, the cuttings can be relocated to their permanent locations.
