How to Propagate a Climbing Hydrangea

Climbing hydrangea uses aerial rootlets to cling to surfaces. Slow to establish, a climbing hydrangea may take five years or more to spread. Propagate a climbing hydrangea by gathering seed, with cuttings or by layering. Seeds need cold stratification to sprout, but germinate and grow readily. Softwood cuttings with aerial rootlets attached will root with little trouble. Serpentine layering--a form of ground layering where lengths of vine are pegged into the soil--also provides many viable shoots.

Things You'll Need

• Clean envelopes
• Plastic bag
• Sterile pots, trays or flats with drainage holes
• Commercial seed starting mix
• Grow lights or fluorescent lights (optional)
• Heating pad
• Heated, covered propagation tray (optional)
• Misting bottle
• Stakes
• Pruning shovel or sharp knife

Instructions

Propagation by Seed

1. Gather seeds two or three months after flowers are fertilized. Put seeds in clean dry envelopes and label with the date. Put the envelopes into a plastic bag and put the bag into the refrigerator or other cold area.

2. Keep seeds at 40 degrees F for two months. Do not use high humidity areas, such as vegetable drawers.

3. Remove seeds and sow in propagation trays or pots filled with moist commercial seed starting mix. Put the seed containers in bright light or use grow lights.

4. Use a heating pad to keep the soil at 70 degrees F. Check soil moisture regularly. Keep soil moist but not soggy. Seedlings should appear in 10 to 14 days.

Propagation by Cuttings

1. Fill pots with a moistened, sterile commercial rooting mix. Use 4-inch containers to accommodate the cuttings during their first growing season.

2. Take 4-inch softwood cuttings from vigorously growing shoots with aerial rootlets and no blooms. Remove leaves below the shoot tip. Stick the cuttings immediately in the pots and firm by hand.

3. Put the cuttings in bright, indirect light or use grow lights 6 inches above the cutting tops. Mist twice a day and do not allow the soil to become soggy.

4. Check for new roots after eight weeks by gently tugging the stem. Leave the rooted cuttings in their containers through the first winter. Transplant outdoors the following spring.

Propagation by Layering

1. Layer your hydrangea at the beginning of the growing season. Choose a branch that is not attached to the climbing structure and bend it toward the ground. Remove a branch from the climbing support or train a young branch down if necessary.

2. Peg the branch to the ground along its entire length. Cover the branch with soil and keep the soil consistently moist.

3. Harvest the shoots that form along the branch at the end of the growing season. Sever the shoots from the parent and each other with a root pruning shovel or sharp knife and allow them to grow for three more weeks to harden.

4. Transplant into pots or other spots in the garden. Keep shoots well-watered after transplanting.

Tips & Warnings

• Use a heated, covered propagation tray to provide ideal conditions for sprouting.

• Climbing hydrangeas require little to no pruning.

• Climbing hydrangeas' cinnamon-colored peeling bark adds winter interest to your garden.

• Hydrangea seeds will not germinate without light.

• Do not propagate hydrangeas during late fall or winter, as they are in a dormant phase.

• Climbing hydrangeas do not like to be disturbed during their first growing season.

References

• University of Florida Extension: Seed Propagation of Woody Ornamentals
• University of Kentucky Extension: Propagating Plants In and Around the Home
• Washington State University: Propagating Shrubs, Trees and Vines

Resources

• University of Minnesota: Propagation
• North Carolina State University Extension: Plant Propagation by Stem Cuttings
• Purdue University Extension: New Plants from Cuttings