Verbena is a popular flowering plant prized for its long blooming season and vibrant clusters of color. It includes a wide variety of types, from mounding annual bedding plants to upright perennial species. Gardeners propagate Verbena to multiply favorite varieties, ensuring an endless supply of genetically identical plants or saving money on new stock. Understanding the right method and timing allows for the successful expansion of this durable, heat-tolerant flower in the garden.
Propagating Verbena Through Cuttings
Propagating Verbena using cuttings is the most reliable method to create clones, guaranteeing the new plant retains the parent’s exact color and growth habit. Take softwood cuttings in late spring or early summer when the plant is actively growing but has not yet set many flowers. Select a healthy, non-flowering shoot that is soft and flexible at the tip, aiming for a length of three to four inches.
Use a sharp, sterile tool to make a clean cut just below a node. This area contains concentrated growth hormones, aiding rooting. Remove all lower leaves from the stem, leaving only a few at the top to reduce moisture loss. Dipping the cut end into a rooting hormone powder or liquid can accelerate root development and increase success.
Insert the prepared cuttings into a well-draining medium, such as a mix of peat and perlite or sterile compost. Place the cuttings around the edge of a pot, ensuring the bare stem is fully buried. To maintain the high humidity necessary for root formation, cover the pot with a clear plastic bag or cloche. Keep the rooting environment warm and bright, shielded from direct sunlight.
Roots typically form within two to four weeks, confirmed by gently tugging the cutting for resistance. Once a robust root system develops, pot the new plants individually into small containers with standard potting mix. This vegetative method successfully carries over specific hybrid varieties that may not reproduce true-to-type from seed.
Starting Verbena from Seed
Growing Verbena from seed is an economical alternative, often used for species like Verbena bonariensis and many annual types. Note that resulting plants may show variation from the parent. To ensure a long bloom season, start seeds indoors 8 to 12 weeks before the final expected frost date. Use a sterile, fine-textured seed-starting mix in flats or cell packs to prevent fungal issues.
Many varieties benefit from cold stratification to break seed dormancy and encourage uniform germination. This involves refrigerating the seeds in a damp medium for two weeks before sowing. Press the prepared seeds lightly onto the soil surface but do not cover them, as most Verbena seeds require light for successful germination.
Maintain the seed trays in a bright location with a consistent temperature, ideally 70 to 75°F. Germination is often slow and sporadic, taking 14 to 30 days. Applying bottom heat with a seedling heat mat helps maintain the required temperature and encourages faster sprouting.
Once green shoots appear, ensure they receive ample light from a sunny window or a grow light source. Position the light source a few inches above the seedlings and raise it as they grow to prevent legginess. Keep the soil consistently moist but never waterlogged, as excessive moisture can lead to damping-off disease.
Caring for New Verbena Plants
The phase following successful rooting or germination focuses on preparing the young Verbena for their permanent location. Before transplanting outdoors, they must be hardened off to acclimate them to harsher environmental conditions like wind, sun, and temperature fluctuations. This involves gradually exposing the plants to the outdoors for increasing periods over a one-to-two-week period.
Once the threat of late-season frost has passed, the plants are ready to be moved into the garden or larger containers. When transplanting, ensure the planting hole is deep and wide enough to accommodate the root ball. Set the plant at the same soil level as it was in its nursery pot, spacing them 12 to 18 inches apart depending on the variety. Adequate spacing allows for air circulation, which helps prevent mildew.
Water the newly transplanted Verbena thoroughly to help settle the soil and eliminate air pockets around the roots. While established Verbena are drought-tolerant, young plants require regular watering to encourage a strong, deep root system. Allow the top inch or two of soil to dry out between watering sessions to prevent root rot.
Verbena are not heavy feeders, but new plants benefit from fertilization during the establishment phase. Begin feeding with a highly diluted, balanced liquid fertilizer two weeks after transplanting, applying it every two weeks. Alternatively, incorporate a slow-release granular fertilizer into the soil at planting time for a steady supply of nutrients.