Phlox is a popular perennial known for its vibrant clusters of flowers. Propagating existing Phlox plants is an effective and inexpensive way to expand garden beds or share favorite varieties. This process allows gardeners to maintain the genetic characteristics of a specific cultivar, unlike growing from seed. Two successful methods for increasing your stock are through stem cuttings and division.
Essential Timing and Preparation
The optimal time for Phlox propagation depends on the chosen method. For division, early spring as new growth begins or late summer into early autumn is best, allowing roots time to establish before temperature extremes. Taking stem cuttings, particularly softwood cuttings, is most successful in late spring or early summer, before the plant has fully bloomed.
Before starting, gather sterile tools, such as sharp shears or a knife, to prevent the transmission of plant diseases. A healthy mother plant provides the most vigorous material for propagation. For cuttings, a specialized rooting medium consisting of sand, perlite, or a well-drained potting mix is recommended to encourage root development. Having a rooting hormone available can significantly increase the success rate of stem cuttings.
Propagation Through Stem Cuttings
Taking stem cuttings creates genetic clones of a specific Phlox variety. Select non-flowering stems from the current season’s growth that exhibit healthy, firm tissue. Avoid stems that are too woody or too soft. The ideal cutting length is typically between three and six inches.
To prepare the cutting, make a clean cut just below a leaf node, as this location contains the highest concentration of root-forming cells. Carefully remove the leaves from the lower one-third to one-half of the stem to prevent rotting once inserted into the soil. If using rooting hormone, dip the cut end into the powder or liquid and gently tap off any excess.
Insert the prepared cuttings into the pre-moistened rooting medium, ensuring the bare nodes are covered. Placing the cuttings in a shaded area away from direct sunlight is crucial for rooting success. Maintaining consistent, high humidity, perhaps by covering the container with a plastic dome, helps reduce moisture loss. This focuses the plant’s energy on generating a new root system.
Propagation Through Division
Division is a straightforward way to propagate Phlox, particularly beneficial for older, established clumps that show reduced flowering or a sparse center. This technique multiplies the plant and rejuvenates its overall health. Water the parent plant thoroughly about a day before dividing to hydrate the tissues and make the root ball easier to manage.
To lift the plant, use a sharp spade to dig a circle around the clump, a few inches outside the main stems, and gently lift the entire root mass from the soil. Once the clump is out, shake or wash away excess soil to expose the roots and the crowns. Separate the root ball into smaller sections using a sharp knife or spade, or by hand for less dense clumps.
Each new division must contain a healthy portion of the root system and at least two or three strong shoots or buds for successful re-establishment. Discard the woody, older center section of the original plant. The newly separated sections are ready for immediate replanting into a prepared garden spot or a temporary container.
Establishing New Phlox Plants
Whether from a rooted cutting or a fresh division, new Phlox plants require careful attention to establish successfully. Newly divided sections should be replanted immediately at the same soil depth they were growing previously. This ensures the crown is positioned correctly relative to the soil line.
Newly potted cuttings, once they have developed a strong network of roots, should be gradually acclimated to outdoor conditions before transplanting, a process known as hardening off. This transition involves placing them in a sheltered outdoor location for increasing periods over several days. All new plants should be watered deeply right after planting to settle the soil and mitigate transplant shock.
Select a final planting site that offers full sun to partial shade, and soil that is consistently moist yet well-drained. Maintaining adequate moisture is especially important for the first few weeks as the roots expand. Providing initial soil requirements, such as adding compost, helps the plants grow vigorously toward maturity.