Oakleaf Hydrangea Propagation

Oakleaf hydrangea can be propagated by a variety of methods.

Oakleaf hydrangea (Hydrangea quercifolia) is a familiar flowering shrub with showy clusters of white blooms that add beauty to the garden from July to September. Hydrangea, a hardy plant that isn't difficult to grow, is easily propagated by hardwood cuttings, softwood cuttings or layering. Propagation by seed is a bit more difficult.

Layering

Layering is an easy way to propagate oakleaf hydrangea any time the shrub has long, flexible branches growing low on the plant. The branch is bent down to the soil and the soil is loosened with a trowel. A thin layer of bark is scraped from the bark where the branch touches the ground, then the branch is secured to the ground with a brick or a large rock. The branch is watered occasionally to prevent the soil from becoming bone dry. In six to eight weeks, the rooted branch can be severed from the parent plant.

Softwood Cuttings

Early summer is the best time to propagate oakleaf hydrangeas by taking softwood cuttings. Several cuttings measuring 5 to 6 inches long are dipped in rooting hormone, then planted in a container filled with commercial potting medium. The container is covered with clear plastic before being placed outdoors in a sunny, protected area away from direct sunlight. The soil is kept consistently damp. The cuttings are usually rooted in about six weeks.

Hardwood Cuttings

Oakleaf hydrangea is propagated from hardwood cuttings taken when the plant is dormant in late autumn or winter. The cuttings, which are firm and won't bend, are from the previous year's growth. The stems are cut into 6- to 9-inch lengths, which are bundled together and stored in a box of sand or sawdust until spring. In spring, the hardwood cuttings are planted in a trench in the ground, with only the top of each cutting remaining above the soil. Successful cuttings are rooted and ready to be planted by the following spring.

Seed Propagation

Seeds are harvested from oakleaf hydrangeas between late September and early October. The seeds are stored in the refrigerator until they are planted in January. Oakleaf hydrangea seeds are planted in shallow trays filled with a commercial seed planting medium. The seeds are placed in a greenhouse where they germinate in about two weeks. When the seedlings develop strong, healthy root systems, they are planted in larger pots where the seedlings remain until the young oakleaf hydrangeas are large enough to survive outdoors.

References

• Texas Agri-Life Extension; Hydrangeas Brighten Landscape; Kathy Fiebig
• Ohio State University Extension; Hydrangeas in the Landscape; Catherine Damm, et al.
• Sunset: Rooting Hardwood Cuttings
• U.S. National Arboretum; Breeding and Propagating Oakleaf Hydrangeas; Sandra M. Reed, et al.
• University of Illinois Extension; Rooting Hydrangea Cuttings in Five Easy Steps; Kathy Hummel; 2006