(Picture courtesy of: http://www.kew.org/science-conservation/plants-fungi/forsythia-suspensa-weeping-forsythia)
BACKGROUND: Hardwood (deciduous) cuttings are those made of matured, dormant firm wood after leaves have abscised. The use of hardwood cuttings is one of the least expensive and easiest methods of vegetative propagation (Hartman, et al, 1997). For this example, we will be using forsythia (Forsythia suspensa (Thunb.) Vahl.). There are two types of cuttings you can do for hardwoods: layering and traditional cuttings. In layering, you take an existing piece of plant and bend it towards the earth. Here you will bury part of the branch under the ground. Rooting will then begin from the parcel underground. The modern cutting method, is one where we will look more closely at in the proceeding steps. Traditional cuttings are cutting a piece of plant off the living (dormant) plant and growing it in a seed bed (container) separate from the existing plant. This is usually done in a greenhouse where temperature, humidity, and watering can be monitored closely.
(picture courtesy of: http://hort201.tamu.edu/YouthAdventureProgram/AsexualPropagation/AsexaulPropagation.html )
WHAT YOU WILL NEED: pencil or waterproof pen for writing; plastic markers to write on for ID; pruning shears or sharp knife for cutting; plastic bags and rubber bands for securing bag to cutting; pots or seedling trays (sizes vary for the amount of plants being propagated); seedling covering (sheets of glass or plastic coverings for plastic trays); suitable planting medium (How- to-Propagate, 2013).
CONTAINER: For single or small numbers of seeds or cuttings, 3–31⁄2-in (8–9 cm) pots are the most suitable size; for larger quantities, 5–6-in (13–15-cm) pots are more economical for propagating multiple cuttings. Plastic pots are easier to use than clay ones, and retain moisture for longer; either type must have drainage holes at the bottom. Biodegradable pots eliminate root disturbance when seedlings are transplanted to larger pots or outside into the ground (How-to-Propagate, 2013).
PLANTING MEDIUM TIPS:
-potting soil from store for non commercial use
-composted material will help in transplanting plants from one container to another, or from a container to the ground
-Vermiculite is sterile-good aeration and holds moisture. Perilite is similar to vermiculite; both are added to household potting soil.
-choose a grade that is suitable for propagation (How-to-Propagate, 2013).
CUTTING PROCEDURE: The cutting for this shrub should be taken in early spring when plant is still in the dormant stage. The new-growth is found on the outermost parts of the shrub and are green and flexible in color (Beal, 2015). You will want to cut 4-6 inches of stem with sterilized shears or knife. In this section of cutting, you will want three to five nodes (looks like a branch has been connected to another branch) present.
(picture courtesy of: http://edenmakersblog.com/?p=4678 )
(Pictures courtesy of: Deep Green Permaculture)
You can use a mixture of alcohol and water or a 10% mixture of Clorox and water to sterilize your tools. In-between cuts, it is best to sterilize. I sterilized between different type of plant cuttings. You can cut the forsythia branch into two or three sections, depending on how tall you want thee initial plant to be. I would recommend using three, although the picture depicted above is of two section cutting. This allows you more propagation pieces, as well as learning which piece of the existing branch grows best, the basal (bottom), medial (middle), or sepal (top).
STORAGE OF CUTTINGS: If planting the cuttings within 24-hours, place in dampened paper towel out of light and in a plastic bag as well (Beal, 2015). I would recommend doing this next step before taking actual cuttings, but you can do it after the actual cutting as well.
PLANTING CUTTINGS: Prepare your greenhouse media (potting soil) in a suitable container for the amount of cuttings you have taken or wish to propagate.Moisten the media with uncontaminated water-your household garden hose should work nicely. Next, pinch off the bottom layer of leaves so that you have about 3 inches of stem showing on each piece you wish to propagate. After this, you will want to wound the bottom most half-inch. To do this, take your sterilized knife and shave off a piece so that the top layer of stem is now removed.
(Picture Courtesy of: Deep Green Permaculture)
By wounding, you are enabling the plant to be exposed to media and nutrients at a quicker pace. This next step is optional- you can dip the base of the stem into a rooting hormone (Deepgreenpermaculture, 2012). Gently insert the stem so that the remaining leaves are still showing.
KEEPING THE CUTTINGS ALIVE: After this is completed, it is best to move the container to a moist, warm-to-slightly-cool (60-70 degrees Fahrenheit) indoor growing space (Beal, 2015). If not in a proper greenhouse, this is where the bags and rubber bands come in handy. By placing the bag over the cutting, you are enabling the plant to stay at a humid temperature. If inside a greenhouse, the thermostat is adjustable and is able to help the cuttings root faster (How-to-Propagate). If propagating outdoors, be sure to keep the cuttings from wind damage and low temperature damage as well as high temperature. If there is to be high wind, create barriers or move the cuttings indoors. If the temperature is too high or too low, move the cuttings indoors as well. Best outdoor propagation methods are made if it is easy to ventilate and water (How-to-Propagate, 2013).
ROOTING HORMONES: (Use concentration instructions on packaging) Auxin. Most hormones come in powder and liquid state. If using a liquid state, you will need to calculate the amount of hormone for the amount of water. The most common hormone is Dip-N-Grow powder. Here, you will simply dip the end of the stem you wish to put into the growing media, and then immediately place it into the growing media. There is no measuring involved.
GROWING THE CUTTING: The rooting will take 4-6 weeks if in proper growing conditions. After the cuttings have begun to take root, move them outside in 8-10 weeks to a place free from wind and enough sunlight to begin growing at a normal state. Be sure to label all plants. Label the different plant pieces (basal, medial,sepal). Also, if you choose to use a rooting hormone, be sure to label those along with the type and parts-per-million (ppm).
Hartmann, H., Kester, D., Davies, Jr., F., & Geneve, R. (1997). Vegetative Propagation. In Plant propagation: Principles and practices (6th ed., pp. 330-340). Upper Saddle River, N.J.: Prentice Hall.
Beal, J. (2015, January 1). How to Grow Forsythia From Plant Cuttings. Retrieved February 25, 2015, from http://homeguides.sfgate.com/grow-forsythia-plant-cuttings-41326.html
Propagating Hardwood Cuttings. (2012, June 29). Retrieved February 25, 2015, from http://deepgreenpermaculture.com/diy-instructions/propagating-hardwood-cuttings/
How to Propagate – Tools For Propagating Plants : HGTV Gardens. (2013, February 9). Retrieved February 25, 2015, from http://www.hgtvgardens.com/garden-basics/how-to-propagate-plants?offset=1