Knowing how to propagate plants from cuttings is one of the most useful skills anyone interested in plants can have. With it, a gardener gains the ability to grow plants without any cost except time and effort. The advantages of taking cuttings are many; it is cheap and convenient, large plants are much quicker to get from cuttings than from seeds, many varieties and hybrids vary if raised from seeds, while cutting gives a plant exactly like the parent. Finally, certain plants such as lavender do not readily reproduce from seed. There are several types of cuttings; softwood cuttings, hardwood cuttings, single-eye cuttings, leaf cuttings, and root cuttings. This article will deal with softwood cuttings, the most common method.
It is easy to learn how to take softwood cuttings, there are numerous articles on line, and for practical experience, just volunteer to work at the Senior Citizens’ Green House in the early spring. Glenna Julian will be glad to show you how and give you immediate on the job training. For best results, take the cuttings when the mother plant is at an intermediate stage of growth in the spring, when the shoots are neither too soft nor too mature. If the shoot bends without snapping like glass or crushes without bending, then it is in the right condition. This is usually May or June for outdoors plants, or earlier in the spring for plants in a hot house. If the stem is too mature, it might not root and grow properly. If the stem is too green and soft, there is a greater chance that it will rot during the rooting process. The most vigorous shoots are not the best cuttings, side shoots of middling strength cut at their base, root the easiest. The best shoots come from the side of the plant, not the top or the very bottom. . If small side-shoots are not available, you can use the tips of longer shoots. The cutting should come from a stem that has not flowered. Study the plant you wish to propagate. Carnations, for instance, only the side-shoots from the center of the stem make good flowering plants. Do not take cutting from plants that have wilted. Therefore, the recommended time for making cuttings is early in the morning. If the plant does show signs of wilting, water it before taking the cuttings.
Take the cutting off the donor plant from ¼ to ½ inch below a leaf or a pair of leaves. It is from this part of the stem below the node that roots are most like to grow. Place the cutting into rooting medium as soon as possible and before it wilts. If this cannot be done immediately, then place the cutting in a damp paper towel, do not put it in water. Also, in the future treatment of the cutting, it is essential that it never be allowed to wilt. Cuttings are generally 4 to 6 inches long. To make the cut, use a sharp, thin-bladed pocketknife, razor blade, or sharp pruning shears. If necessary, dip the cutting tool in rubbing alcohol or a mixture of 1-part bleach to nine parts water to prevent spreading diseases.
Remove the leaves from the lower one-third to one-half of the cutting (Figure 1). On large leafed plants, the remaining leaves may be cut in half to reduce water loss and conserve space. Species difficult to root should be wounded. That is, a small area below the bottom node is scraped or small cuts made into the stem.
There is a debate among gardeners if a rooting compound is needed. Some people use it while others do not. If you do use it, prevent possible contamination of the entire supply of rooting hormone by putting some in a separate container before treating the cuttings. Any material that remains after treatment should be discarded and not returned to the original container. The rooting medium (the soil you put the cutting in) should be sterile, low in fertility, and well drained. It should retain enough moisture so that frequent watering is not necessary. Materials commonly used are coarse sand, a mixture of one-part peat and one part vermiculite (by volume), or one part peat and one part sand (by volume). Vermiculite by itself is not recommended because it compacts and holds too much moisture. There are plenty of commercial rooting/potting soils available at the garden store. Moisten the potting medium before using it. Insert the cutting one-third to one-half its length into the medium. You need to stick them in far enough that they stand straight up. Maintain the vertical orientation of the stem (do not insert the cuttings upside down). Space cuttings far enough apart to allow all leaves to receive sunlight. Water again after inserting the cuttings. Now if you do not have a green house and most of us do not, here is where the procedure became tricky for me. The experts always recommended that the cutting/container then be placed in a plastic bag or that some type of plastic tent be made in order to keep the cutting and rooting soil from drying out. This is something that was hard for me to understand. However, at one site, there was a tip on using clear plastic drink cups to cover the growing pot. The clear plastic drink cup being either slightly larger and fitting over the lip of the growing container or slightly smaller and fitting snugly down inside. The plastic cup creates a mini-greenhouse for the cutting. With my luck, I got a growing container and drink cup that were the same size. So after placing the cup over the container, duct tape was used to seal the two together. It worked like a charm. Just remember to make a drain hole in the growing pot.
Place cuttings in bright light. NEVER PLACE NEW CUTTINGS IN THE SUN. They will cook in the plastic. And even if they are not in plastic, they should be placed in a bright shady area. For this spot, I choose an area under my deck away from the direct sun. Check the plants every day or so, but do not water again until top of soil begins to feel slightly dry. Over watering will cause cuttings to rot.
Depending on the plant, the cuttings could root in 2-3 weeks. Some cuttings root in as little as one week. If a tug on the cutting resists the pull, it is rooting. If the slip pulls out easily, then it has not rooted. Also, some plants are slower to root. Hydrangeas are notably slow, taking up to two months. Once the plant resists being pulled, and is rooted, it can be taken out of the protective container. Depending on the type of plant you have rooted, the time for transplanting could be at once, or in the fall, or it might need to be over wintered. For plants that need it, getting cuttings through the over wintering without a greenhouse is the trickiest part. Starting new cuttings in late spring or early summer will give them the best chance for surviving the winter.
For plants that require over wintering, here are some suggestions. Experts recommend sinking pots of cuttings into the ground and covering them well with lightweight mulch or placing smaller pots of cuttings next to a foundation and covering them with large clay pots for the winter. While some people manage to take cuttings through the winter indoors, this also has its drawbacks. Not being an expert, I choose bringing my pots inside for the winter. This next section is entitled: “Mistakes I made”, or how “I Kill My Own Plants”. The plastic cup covers worked very well for me. My plants would receive bright, but indirect light, I placed the tray of cuttings under my deck close to the house foundation. Out of the tray of cuttings, several cuttings did become soft and then rot. I realized that the plants, which had spoiled, came more often from the side of the tray facing the wall. Next time I make cuttings, I will switch the orientation of the tray from time to time so each plant gets equal light. The last cuttings I made were for a hydrangea, and they had to be over wintered. I decided to bring them inside the basement when the temperature went below freezing. However, I made a mistake and they were left outside below freezing. This did not kill all the plants, just some of them, but it did damage them all in some way. So always err on the side of bringing in or otherwise preparing the plants for winter sooner rather than later. The last way that I damaged my plants, was once on the inside, I would visibly check my plants as I walked by. However, when physically checked them, I discovered that several of my best cuttings had dried completely out. I have over wintered lavender before and it was not this sensitive. Making the cuttings and rooting of a plant is relatively easy but know the requirements of the plant you are rooting, and make your decisions based on this. Once the technique plant propagation is acquired, it enables the gardener to fill a landscape with plants identical to ones which have already thrived there.
A Styrofoam and a clear plastic cup make a great green house to start cuttings.
A month after being taken these Hydrangea cuttings are healthy, but still not rooted.
The following spring, this Hydrangea plant will be ready for planting:
* This article was previously printed in the June 2007 SCAMGA newsletter. Sadly, our friend and fellow Master Gardener Roger Simpson has passed on. He is missed.