The trumpet vine, Campsis radicans, is a deciduous woody vine known for its vibrant, trumpet-shaped flowers that attract hummingbirds. This plant exhibits vigorous growth, allowing it to quickly cover fences, arbors, and other structures. Vegetative propagation is the preferred method for creating new plants identical to the parent. This guide details two reliable methods: taking stem cuttings and simple layering.
Timing and Preparation
For stem cuttings, the optimal period is late spring to early summer, when new growth is in the softwood stage, meaning it is flexible but not yet hardened. Layering can be performed anytime the vine is actively growing, typically from spring through mid-summer.
Gathering supplies involves having a sterile potting medium, such as a mix of peat moss and perlite or coarse sand, placed in containers with drainage holes. Use a sharp, sterilized knife or pruners to make clean cuts and prevent disease transmission. Rooting hormone powder or gel increases the likelihood of successful root development, though it is not mandatory. For layering, you will also need metal wickets or garden staples to secure the stem to the ground.
Propagating with Stem Cuttings
Select healthy, non-flowering material from the current season’s growth. Identify semi-hardwood stems that exhibit a balance between maturity and flexibility. Each cutting should be four to eight inches long and contain several nodes, which are the small bumps where leaves emerge.
Use a sterilized tool to make a clean, angled cut just below a node, as this is where root-forming cells are concentrated. Remove all but the top one or two sets of leaves to reduce water loss through transpiration. Lightly scrape a small section of the bark at the base of the cutting to expose the inner cambium layer, which encourages root initiation.
Dip the prepared end into rooting hormone, coating only the bottom inch. Insert the treated end into the moist, well-draining rooting medium, burying at least one node beneath the surface. Place the container in bright, indirect light and maintain a consistently humid environment, perhaps by covering it with a clear plastic dome or bag.
Propagating with Layering
Begin by locating a long, flexible stem near the base of the vine that can be bent down to touch the soil surface. This method capitalizes on the continuous supply of water and nutrients from the parent plant, supporting the new growth until it is self-sufficient.
About nine inches from the stem tip, carefully wound the underside by gently scraping away a small section of bark or making a shallow nick. Applying rooting hormone to this wounded area can stimulate quicker root growth, though the vine often roots readily without it. Gently bend the stem down and secure the wounded section firmly against the soil using a garden staple or heavy stone.
Cover the wounded area with several inches of soil, ensuring the tip of the stem remains exposed and pointed upward. Keep the soil over the buried section consistently moist throughout the growing season. This slow process allows robust roots to develop over several months, often requiring the layer to remain attached until the following spring for the best results.
Care of New Plants and Transplanting
Once the cuttings or layers have established, they require proper care before transplanting. For cuttings, a gentle tug on the stem after about a month should meet slight resistance, indicating that roots have begun to form. New layers can be separated from the parent plant by cutting the stem just behind the newly rooted section once the growth is visibly established.
Before moving the young plants outdoors permanently, they must be gradually acclimated to the harsher conditions of direct sun and wind in a process known as hardening off. Begin by placing the pots in a sheltered outdoor location for a few hours each day, slowly increasing the duration over a week or two. This step prevents the sudden shock of transplanting from damaging the new growth.
When selecting a final location, consider the trumpet vine’s aggressive growth habit, as its aerial rootlets can damage wood or masonry. Planting near a strong trellis or in an area that can be easily mowed, such as a lawn edge, helps control the spread of suckers that emerge from the roots. Ensure the site receives full sun, as ample light encourages the greatest flower production from the established vine.