Starting and Propagating Hydrangeas From Clippings and Cuttings
Hydrangeas are easily propagated by taking clippings from an established Hydrangea plant’s growth section called the softwood. The softwood is the section between the really soft green new growth at the end and the really hard woody growth at the bottom. Although propagation is sometimes possible using the softer new growth and the harder old growth, it is not as easy.
It is generally best to take the cuttings in the summer months (June, July, August). Depending on the climate/zone you’re in, you may be successful during earlier or later parts of the year. Gather your cuttings in the early morning if possible. Take a container filled with water when gathering your cuttings, so that you can immediately place them in the water. Keep the stem cuttings covered and out of direct sunlight.
Prepare the cuttings by making a fresh cut just below a leaf joint and removing that first set of leaves from the bottom. If the cutting has a bloom on it, clip that off as you want the plant to devote all of its energy to forming roots. Final cuttings should generally be somewhere around 4 to 6 inches in length.
Place some rooting hormone (available from your local nursery or home garden center) into a separate container or in a small pile. Wet the bottom end of the stem and then dip the stem tip in the rooting stimulant, taking care to cover and coat the node area well. Tap the stems gently to remove the excess stimulant if using a powder. Discard the remaining rooting compound as you don’t want to risk cross contaminating other cuttings.
Plant the cuttings in small pots or containers filled with 50% peat and 50% sand or “soilless” potting mix as that will help them to drain properly. Place pots in a window sill or somewhere that allows for some light and fairly consistent temperatures. To simulate greenhouse conditions, wrap in a plastic bag or cut the bottom off of a 2-liter plastic soda bottle or milk jug and place it over the container. Keep moist, but not soaked.
In about four to six weeks, the cuttings should be established and have rooted enough to allow them to be transplanted outside into a sheltered bed or larger container. If you live in a colder climate, you may wish to allow the plant to remain inside for the first winter. Periodically pinch top growth to encourage the plant to become bushy.
Another method which can be used is known as ground layering. Ground layering allows the stem to stay attached to, and receive nutrients from, the mother plant while it is forming its own roots. When ground layering, choose a low branch that is close to the ground. Dig a shallow trench below this branch and water the area. Scratch off some of the bark to expose the inner flesh of the stem, then bend the branch at that place to the ground (being careful not to break it) in a U shape. Using rooting compound on the wound will further encourage root growth. Bury the branch at the U, making sure the scraped area is covered. Place a heavy object on top of the branch, such as a brick or rock, to keep it in contact with the soil and to help seal in the moisture.
There are many deciduous garden shrubs and trees as well as some evergreens that can be propagated using these methods. Some include Barberry, Bittersweet, Butterfly Bushes, Cotoneaster, Deutzia, Euonymus, Forsythias, Honeysuckles, Lilacs, Magnolias, Privets, Roses, Sweetshrub, Viburnum, and Weigela. Experiment and multiple your collection or share with friends and family.