Weeping cherry trees (Prunus pendula or Prunus subhirtella) are valued ornamental plants, celebrated for their graceful, cascading branches and abundant spring blossoms. Propagating them allows gardeners to create new plants from an existing specimen, expanding a collection or sharing with others.
Understanding Weeping Cherry Propagation
Propagating weeping cherry trees presents unique considerations due to their characteristic weeping form. Most commercial weeping cherries are specific cultivars grafted onto a different rootstock. This grafting process creates the desired weeping habit and influences the tree’s size and vigor.
While cuttings can be used, the resulting plant may not exhibit the iconic weeping shape unless subsequently grafted. Grafting is the preferred method for replicating the parent tree’s true-to-type weeping form. This involves joining a scion (the weeping cherry portion) to a compatible rootstock, ensuring the new tree maintains its desired characteristics.
Propagating Weeping Cherry by Grafting
Grafting is the most common and reliable method for replicating a weeping cherry’s specific characteristics. This technique joins a scion from the desired cultivar onto a compatible rootstock. The optimal time for grafting is late winter or early spring, just before the rootstock breaks dormancy.
Gather sharp grafting knives, grafting tape or wax, healthy scion wood, and rootstock. Scion wood should be collected from the previous season’s dormant growth, ideally pencil-thick with healthy buds. Compatible rootstocks often include Prunus avium or other Prunus species.
The whip-and-tongue graft is a common technique. It involves making a long, sloping cut on both the scion and rootstock, then a small, downward-angled cut to create a “tongue” on each. Aligning these tongues ensures maximum cambium contact for a successful graft union. Alternatively, a cleft graft can be used when the rootstock is significantly thicker, splitting it to insert a wedge-shaped scion.
After aligning the cambium layers, firmly bind the grafted area with grafting tape to hold the scion and rootstock securely. Applying grafting wax over the tape helps seal the union, preventing moisture loss and protecting against pathogens. Place the newly grafted plant in a sheltered location with consistent moisture and moderate temperatures to encourage healing and growth.
Propagating Weeping Cherry by Cuttings
Propagating weeping cherry trees from cuttings is an alternative method, though a plant grown from a cutting may not develop the classic cascading form without subsequent grafting. The best time to take softwood cuttings is in early summer, when new growth is pliable. Hardwood cuttings can be taken in late fall or winter after leaf drop.
Gather clean, sharp pruning shears, rooting hormone, and a well-draining rooting medium like perlite and peat moss. For softwood cuttings, select healthy, non-flowering stems 4-6 inches long, cutting just below a node. Remove lower leaves to expose nodes. For hardwood cuttings, choose mature, dormant stems 6-10 inches long with several nodes.
Dip the cut end of each prepared cutting into rooting hormone. Plant cuttings into pots with the rooting medium, ensuring at least one or two nodes are buried. Space cuttings so they do not touch.
To create a humid environment, cover the pots with a clear plastic bag or place them in a propagation dome. Mist cuttings regularly to maintain high humidity, but avoid waterlogging the medium. Rooting typically occurs within several weeks to a few months, depending on cutting type and environmental conditions.
Aftercare for New Weeping Cherry Plants
New weeping cherry plants require consistent moisture. Water regularly to keep the soil moist but never waterlogged, as excessive wetness can lead to root rot. Ensure proper drainage in pots or planting sites.
Provide bright, indirect light or partial shade initially, gradually acclimating them to more direct sunlight. Light fertilization can begin once the plant shows active growth, using a balanced, diluted liquid fertilizer. Protect new plants from extreme temperatures, strong winds, and intense sunlight.
Monitor young plants for pests or diseases, addressing issues promptly. Once the root system is well-established and the plant has grown sufficiently (typically after one growing season), transplant it to a larger container or its final outdoor location. Ensure the new site offers well-drained soil and adequate space.
Troubleshooting and Tips for Success
Propagating weeping cherry trees can present challenges, with common issues including graft failure or cuttings failing to root. Disease or pest issues can also affect young plants, especially if environmental conditions are not ideal or tools are not sterile.
Patience is a key factor in successful propagation; root development and graft union take time. Always use sterile tools, such as grafting knives and pruning shears, to prevent disease spread. Maintaining consistent environmental conditions, including temperature and humidity, is also important for encouraging growth.
Selecting healthy, vigorous parent material for both scion wood and rootstock significantly increases success. Ensure scion wood is dormant and free from disease or damage. Careful attention to detail and persistent effort can lead to successful propagation outcomes.