Some of the best tips for growing hydrangea cuttings are to choose new growths and to prepare the cutting by stripping any unnecessary leaves before attempting to root them. While using a root hormone is not always necessary, it can make growing hydrangea cuttings easier. In general, cuttings should be started inside of a well-drained pot, as it is difficult to protect new cuttings from climate changes when started in the ground.
It is nearly impossible to grow hydrangeas from an old branch, as these are typically not actively growing. One of the most important parts of growing hydrangea cuttings is to choose a stem from the plant that is young and has not yet flowered. Old branches will typically be brown or dark green, while new growth is a vibrant green color. While a new growth cutting is necessary, the stem needs to be strong enough to develop roots. In general, a bright green branch that is at least 6 inches (15 centimeters) long will root under the right conditions.
Prior to planting the cutting, any small leaves need to be removed from the plant. In most cases, it is only necessary to leave two to three leaves at the top of the branch. The top set of leaves that are remaining should be cut in half across. This will help to prevent the plant from losing too much water while it is rooting. Preparing the cutting before attempting to root it will help to ensure that the hydrangea not only develops into a plant, but also that the root system will be strong enough to withstand transplanting once the hydrangea cutting begins to grow.
Growing hydrangea cuttings is relatively easy when the cutting is prepared and planted correctly. Unlike other plants, the hydrangea can successfully root without a rooting hormone, although this gardening product can make it easier for the stem to develop roots. To increase the chances of the cutting growing, dip the bottom of the stem in a rooting hormone just prior to planting. When doing this, it is important to follow the manufacturer’s directions, as too much rooting hormone can actually prevent the hydrangea cutting from developing roots.
As with most young plants, hydrangea cuttings require a moist, warm space in order to develop. Despite this, once cuttings are placed in a pot, it is important that the soil does not become overly moist, as this can rot very young roots. A well-draining pot, with multiple holes in the base, will help to protect the hydrangea cuttings from root rot. Starting the cutting in a pot makes the cutting mobile, allowing gardeners to protect the hydrangea from direct sunlight, which can damage it.