Select a healthy stem that hasn’t bloomed yet and snip a 6-inch section.
Remove the lower leaves and cut the remaining leaves in half lengthwise.
Dip the cuttings in rooting hormone and plant them in small containers filled with vermiculite, coarse sand, or a mix of both.
Keep the soil slightly moist and cover the container with a plastic bag or dome to retain moisture.
Place the container in a bright spot with indirect light and wait for about a month for the cuttings to develop roots.
How to Grow a Hydrangea Tree from Seed
Growing hydrangeas from seeds is possible but can be challenging. Most gardeners prefer propagating by cuttings. However, if you want to give it a try, here’s what you need to do:

Allow some flowers to develop on the plant and then harvest them and let them dry in paper bags.
After a week, shake the bag to separate the tiny seeds from the flower heads.
In fall, you can sow the seeds directly into the ground or start sowing indoors in early spring.
Spread the seeds over the surface of a container filled with potting soil and keep the soil slightly moist.
Place the container in full sun and expect the seeds to germinate within a few weeks.
Potted and Repotted Tree Hydrangeas
If you have a container-grown hydrangea, it may need to be repotted every two years. Here’s what you need to know: