How To Propagate, or Clone, Deciduous Plants with Hardwood Cuttings
by Jeff Edwards
There are two effective ways to take hardwood cuttings of deciduous plants. The question becomes, is one technique better than the other? That's hard to say. Depending on what variety you're rooting, what kind of soil conditions exist in your yard, and what Mother Nature has in store for the upcoming winter months. Each method has produced successes and failures. Truth be told, only through experimentation can one determine what works best for you. Your best bet is to try both methods to see which one works best for your particular variables.
Prior to propagating deciduous plants using hardwood cuttings, you should wait until the mother plants have gone completely dormant. Dormancy does not occur until your area has had a nice hard freeze where the temperature dips below 32 degrees Fahrenheit for a period of at least several hours.
Deciduous Propagation Method Number One
The difference between taking softwood and hardwood cuttings off deciduous plants is that for softwood you take tip cuttings from the newest growth at the very ends of branches, whereas with hardwoods, you can turn a single branch into several individual cuttings.
As an example, branches on a plant such as Forsythia can typically grow as much as four feet in a single season. In this case, the propagator can use the entire current years growth to make hardwood cuttings. Depending on it's length, you can often get as many as eight cuttings from a single branch.
Grape vines are extremely vigorous plants. A single vine often grows up to ten feet or more in a single growing season. Since that growth is all current year growth, the entire length of the vine can be used to make hardwood cuttings. There is considerable space between the buds, so cuttings should be much longer than with most other deciduous plants. The average hardwood grape vine cutting length is about 12 inches but due to the wider internodal spacing, it will still only have 3 or 4 buds. Since bud spacing on most other deciduous plants is much closer, the cuttings will only need to be about 6 to 8-inches long.
Hardwood cuttings must be taken during the winter months when the plant is dormant. Find a protected working area like your garage or basement to protect you from extreme weather. If you are blessed with some nice weather after the first freeze, then working outside is not a problem.
Making a hardwood cutting from a deciduous plant is actually quite easy. All you need to do is collect some branches, otherwise known as canes, from the mother plants. Snip these canes into individual cuttings about 6 inches long. Since the plant is dormant, the canes won't have any leaves on them. Closer examination, however, reveals that the canes have some little bumps along the cane. These bumps are called bud unions which are the following years leaf buds. They are commonly referred to as nodes. Your best best when taking a hardwood cutting of a deciduous plant, is to make your bottom cut just below a node, as the butt end of the cutting. Make the cut at the top of a cutting about 3/4 of an inch above a node.
Making your cuts in this manner serves two distinct purposes. First, it makes telling what part is the top of your cutting and what part is the bottom much easier. It also benefits the cutting in two different ways. When you cut a plant above a node, the balance of the stem above that node will die back to where the top node is. By the same action, the 1/2-inch of stem below the bottom node, the one we'll stick in the rooting media, will die off as well. However, having a section of dead wood rotting in our rooting media is not a good idea as it serves as a place for disease to begin and insects to hide.
The above photo includes a sampling of hardwood cuttings made by Mike McGroarty of FreePlants.com, that are ready to be planted out or buried, depending on which technique you employ. The lower portion of the cuttings are on the right. Notice how the cuts are made right below the nodes, but don't cut into them. This photo shows cut examples of a Burning Bush, a Red Twig Dogwood, a Rose of Sharon, and a Purple Sandcherry.
Believe it or not, it is actually helpful to slightly injure a plant when you are forcing it to develop roots. When plants are injured, a callous develops over the wound for protection. The build up of this callous is necessary before roots will develop. Making your cut just below a node on the bottom of a cutting will result in the plant developing a callous and from the callous, roots.
The purpose of leaving 3/4 inch of the stem above the top node is to provide protection for the top node. Leaving this section prevents the buds from being damaged while you are handling and planting the cuttings. You can this tip on the cutting as a handle to stick without harming the buds. Make the cut at the top of the cutting with about a 45 degree angle to help shed water away from the cut end of the cutting which will help to prevent disease and insects.
Once you have taken all of your cuttings, dip the bottom portion in a rooting agent. It's important to use a stronger rooting compound that is formulated for hardwood cuttings. You can find a wide variety of rooting compounds on line at better garden centers and hydroponic shops.
Now it's planting time. Line your cuttings up so the butt ends are all on the same side and tamp them together so the ends are even. Then tie them into bundles. Find a spot in your garden that gets full sun. The next step is to dig a hole that is about 10 inches deep and large enough to hold all of your cutting bundles. While counterintuitive, place the bundles of cuttings in the hole upside down, so that the butt ends of the cuttings are pointing towards the sky. The butt ends should be about 3 inches below the surface. Next, fill the hole in completely with soil and mark the location in a fashion that you can find the cuttings next spring.
As the winter progresses, your cuttings should develop callouses and possibly even some roots. The reason for placing them in the hole upside down is so that the butt ends are closest to the surface, where they can be warmed by the sun, which creates favorable conditions for root development. The upside down configuration also discourages unwanted top growth at this stage.
Don't keep checking on the cuttings, just leave them alone until about mid spring or after all danger of frost has passed. The buds will have begun to develop over the winter and will be quite fragile as you dig them up. The danger posed by frost if you dig them out too early could result in considerable damage. It's always best to leave hardwood cuttings completely buried until the danger of spring frost is gone.
After the last freeze, dig the bundles of cuttings up very gently, so as not to damage them. Carefully cut open the bundles and closely examine the butt ends. If all went as planned, you should see some callous build up. However, even if you observe no callous, you still want to plant them anyway.
You don't need a special bed of sand for hardwood cuttings. Just plant them in a sunny location in your garden that is well draining, with compost rich topsoil.
To actually plant the cuttings, dig a very narrow trench, or using a spade, make a slice in the ground using a prying motion. Place the cuttings in the trench with the butt ends down, burying about one half of the cutting with just a few buds left above ground. Fill in around the cuttings with loose soil and tamp it in lightly to make sure there are no air pockets. Keep them watered on a regular basis, making sure the soil isn't so wet that the cuttings rot.
If all goes well, within a few short weeks, your cuttings will start to produce leaves. You will invariably lose a few due to insufficient roots to support the plant. The remaining cuttings will develop roots while they leaf out. By autumn, the cuttings that have survived should be pretty well rooted. You have the choice of transplanting them once they go dormant, or alternatively, you can wait until spring. You must make sure that you transplant them before they come out of dormancy if you wait until spring.
Deciduous Propagation Method Number Two
The second method for propagating deciduous plants with hardwood cuttings is identical to method number one, up to the point where you bury the the cuttings over the winter.
Method two doesn't require you to bury the cuttings at all. Using this method, you simply plant the cuttings out as soon as you take and prepare them in the late fall. We're just skipping the step where the cuttings get buried underground over the winter months.
Plant them exactly the same way as described for the first method. Again, treating them with a rooting gel or agent before planting will help promote new root growth.
The great thing about propagating hardwood cuttings of deciduous plants is that you can do it throughout the winter as long as the ground isn't frozen solid.
You can successfully take hardwood cuttings from most deciduous shrubs. However, some of the more refined varieties of deciduous ornamentals may present further issues. If you're curious about how to propagate a particular variety of plant, just click on "How to Find the Propagation Technique that is Right for Your Plant".
Copyright © 2013 by Jeff Edwards
Photograph courtesy Michael McGroarty, a hands-on plant propagation expert, proprietor of the plant propagation site, FreePlants.com and author of several books, publications and videos about plant propagation techniques.