Noted for its massive cluster of summer blooming flowers (in white, blue or pink) the hydrangea is a flowering shrub that grows well in moist soil and full or partial sun. Some hydrangea bushes will only produce sterile flowers, while other will produce both sterile and fertile flowers. The most attractive are the sterile blossoms, which cannot produce seeds. The fertile flowers are small, star shaped blossoms, typically located at the center of the flower cluster. Hydrangeas can be propagated by rooting branches that are still attached to the parent bush.
Remove the soil and mulch from an area to the side or behind an existing hydrangea bush.
Bend a low growing branch so that it touches the soil area you have exposed. Do this gently to avoid breaking the branch.
Cover the section of the branch touching the ground with soil and weight the branch down with a rock or brick. There should be a 6- to 12-inch branch tip sticking out from under the rock or brick.
Keep the soil moist for at least two weeks. That will stimulate root growth on the branch.
After two weeks, hold the branch in place and gently lift the brick or rock to see if roots have developed. If not, replace the brick and check back in another week or so.
One the roots have developed, cut the rooted branch from the parent tree. Use sanitized gardening shears (dipped in bleach or alcohol before use).
Dig up the newly rooted section of the branch, carefully, and replant in a shady area. Keep moist until the plant is well established and healthy.