How to Propagate Oakleaf Hydrangea From Cuttings

Oakleaf hydrangea offers multi-season appeal with its distinctive lobed foliage, large flower cones, peeling winter bark, and rich autumn leaf color. Propagating this plant is a straightforward method for gardeners to create more shrubs to expand their landscape or share with others. This process allows you to grow new, genetically identical plants from your favorite specimens at no cost.

Best Time for Propagation

There are two primary windows to take cuttings, defined by the maturity of the stem growth. The first and more successful method is taking softwood cuttings from late spring to early summer. At this time, the plant’s new growth is green, flexible, and in a state of active growth that encourages it to form roots quickly.

The second opportunity is taking hardwood cuttings during the dormant season, from late fall through winter. These cuttings are from the current year’s growth that has fully matured and turned woody. While this is a viable method, hardwood cuttings are generally slower to root and have a lower success rate.

Propagation from Cuttings

Before you begin, gather your materials. You will need the following:

• A clean, sharp pair of pruning shears or a knife
• A small pot with drainage holes
• A sterile, well-draining rooting medium, like a 50/50 blend of perlite and peat moss, which provides good moisture retention and aeration
• Rooting hormone, available as a powder or gel, to encourage root development
• A clear plastic bag to create a humid environment

Select a healthy, non-flowering stem from the current season’s growth. Using your sharp pruners, take a cutting that is four to six inches long, making the cut just below a leaf node. Once you have your cutting, remove the lower sets of leaves, leaving only two or three at the top. If the remaining leaves are large, you can cut them in half horizontally to reduce moisture loss through transpiration.

Pour a small amount of rooting hormone into a separate dish to avoid contaminating the main container. Moisten the cut end of the stem, dip it into the rooting hormone to coat the bottom inch and any exposed nodes, and tap to remove any excess. Use a pencil to create a hole in your rooting medium and insert the cutting deep enough to bury at least one leafless node. Firm the medium around the stem to ensure good contact.

Caring for New Cuttings

Keep the rooting medium consistently moist but never saturated, as waterlogged conditions can lead to rot. High humidity is an important factor for success. Create a miniature greenhouse by placing a clear plastic bag over the pot, using small stakes if needed to keep the plastic from touching the leaves. This traps the moisture necessary for the cutting to thrive before it has roots.

Place the potted cutting in a location that receives bright, indirect light, as direct sunlight is too intense and will cause it to wilt. A spot near a north-facing window or in a shaded part of a greenhouse is ideal. Check for root development, which typically begins within four to six weeks. A gentle tug on the stem is the best way to test for roots; if you feel resistance, it signifies that a root system is forming.

Transplanting Rooted Cuttings

Once the cutting has developed a robust root system, it must be gradually acclimated to outdoor conditions. This process, known as hardening off, involves exposing the plant to increasing amounts of direct sunlight and outdoor temperatures over one to two weeks. Start by placing it in a sheltered, shady spot for a few hours a day, slowly extending its time outside.

After the hardening-off period, the hydrangea is ready for its final position. Dig a hole that is as deep as and slightly wider than the root ball. Gently remove the plant from its rooting pot, place it in the hole, and backfill with soil, making sure the top of the root ball is level with the surrounding ground. Water the new transplant thoroughly to settle the soil and provide immediate hydration.