It’s pretty easy to clone a hydrangea cultivar by rooting a cutting from that plant. But you can also propagate hydrangeas by collecting and sowing hydrangea seeds.
Growing hydrangeas from seed are exciting because seed-grown hydrangeas are unique. They are not clones of their parent plants and you don’t really know how a seed will turn out. Each of your seed-grown hydrangeas will be considered a new cultivar.
How to Grow Hydrangea from Seed
You can start sowing hydrangea seeds immediately after you harvest them. Alternatively, save them in a cool place until spring and start sowing them then.
In either case, the surface sows the seeds in a flat filled with potting soil. Keep the soil moist and protect the seeds from cold and wind.