Since hydrangeas rarely produce seeds, how can the home gardener propagate these showy and spectacularly blooming bushes? Just follow these few simple and straightforward steps.
Step 1 - Cut Hydrangeas For Rooting
Healthy hydrangea bushes make for the best cuttings. Be sure to cut new growth (green stems) at least 2 inches below a pair of leaf nodes. Early morning is the best time to take the cuttings. If not rooting immediately, refrigerate the cuttings overnight. Initial cutting should be 4 to 5 inches long. Terminal cuttings should be taken from stems without a flower.
TIP: Our expert gardening advisor, Karen Thurber notes, "Early summer is the ideal time to take soft wood cuttings."
Step 2 - Prepare the Rooting Media
Hydrangeas are known to root fairly quickly in different soil conditions, but to ensure the best and quickest propagation, use 1 part peat or potting soil and 1 part fine grade perlite, vermiculite or sand. Sand (mason’s grade or screened) is preferred to perlite, due to its excellent drainage.
Mix perlite (or sand) and peat thoroughly together. Fill several small pots or a propagation tray to the top. Soak tray or pots in a water-filled sink for at least 30 minutes, gently spraying the surface with water occasionally.
Alternatively, wet the mixture before potting.
Step 3 - Trim Hydrangea Leaves
Using scissors or sharp and clean pruning shears, trim the hydrangea leaves. Leave about 2 inches per leaf. Cut perpendicular to the leaf veins. Trimming the leaves reduces the surface area, which will reduce transpiration from the leaf.
TIP: Karen advises, "When trimming the leaves of the hydrangea, it is only necessary to trim the largest leaves."
Step 4 - Cut Hydrangea Stems
To fit into the propagation tray or pot, cut the stems to include at least 1 leaf node or terminal bud per cutting. A leaf node is where the leaves attach to the stem. The terminal bud, also called apical bud, is the stem’s actively growing part and will become next year’s flower.
Cut above the first set of nodes from the stem’s bottom, leaving 1 to 2 inches below the leaves to stick into the rooting media. Cuttings ready to plant will be 3 to 4 inches long.
Step 5 - Root the Cuttings
Use rooting hormone (available at garden centers) to encourage the new hydrangea cuttings to grow. There are liquid and powder rooting hormone products available, including Dip’n Grow and Take Root. If using liquid, take a bunch of leaves and plunge the stems into the liquid rooting hormone for a count of five, then stick in the center of the propagation tray up to the base of the leaves.
TIP: Karen adds, "Rooting hormone will speed the rate of rooting, but is not required to root hydrangeas."
Rooting in a cup is another method of propagating hydrangeas. Use a styrofoam cup and add the rooting mixture, apply the growth hormone and plant.
Try not to allow leaves to touch each other in the trays, or they may rot.
Step 6 - Mist
After potting, use a spray bottle to thoroughly mist the cuttings. Don’t over water, but do mist sufficiently to wet thoroughly. Continue to mist 3 times a day the first week unless in full sun, when more misting is required. Never let the plant dry out or wilt too much between waterings and avoid misting in late evening.
TIP: Karen suggests, "To reduce the amount of required misting, place a plastic 'tent' over the cuttings. Do not allow the leaves to touch the plastic, doing so will make them more susceptible to disease. Place in bright shade, never direct sunlight."
Roots will begin to form in as little as a week on some varieties, but most varieties will take 2 to 3 weeks. Newly propagated hydrangeas will mature in about 6 to 8 weeks. The best time to plant them outside is in early fall.
TIP: Karen adds, "Ground Layering is another technique used to propagate hydrangeas. Ground layering is achieved in the landscape by bending a branch from the plant, to the ground, and burring a section of the stem."