How to Propagate Creeping Phlox

Creeping phlox is a resilient ground cover with a dense, mat-forming habit and vibrant spring flowers. Its ability to spread makes it a favorite for gardeners, and this natural tendency also makes it straightforward to propagate. Multiplying your phlox is a simple way to expand its presence in your garden or share with others, as the process offers a high rate of success.

When to Propagate Creeping Phlox

The two most favorable windows to propagate are in the spring, just after the blooming cycle has finished, or in the early fall as temperatures cool. In late spring, the plant has expended energy on flowering and is entering a phase of vegetative growth. Its energy reserves are high, which helps new divisions or cuttings establish themselves quickly.

Propagating in the early fall offers different advantages. The milder weather and cooler soil temperatures reduce the risk of heat stress on the newly separated plants. This allows them to focus on developing a strong root system before winter dormancy. Propagating during the peak heat of summer should be avoided, as high temperatures can dehydrate and stress new plants before their roots establish.

Propagating by Division

The most common method for propagating creeping phlox is division, which is best for mature plants that have grown into substantial clumps. Prepare the new planting location so the divisions can be replanted immediately, minimizing root exposure. Water the parent phlox clump thoroughly a day or two before you plan to divide it.

Using a sharp spade or garden fork, carefully dig around the perimeter of the entire plant and lift the clump from the ground. Try to keep the root ball as intact as possible. Once lifted, you can gently shake off excess soil. Often, you can pull the clump apart by hand, but a sterilized knife can be used for densely packed clumps.

Each new section should have a healthy portion of both top growth and an established root system. Replant these divisions right away at the same soil depth as they were in their original location. Planting them too deep can lead to rot. After planting, water the new divisions thoroughly to help settle the soil and reduce transplant shock.

Propagating by Stem Cuttings

If you prefer not to disturb the parent plant, propagating from stem cuttings is an excellent alternative. Take cuttings in late spring or early summer when the plant is in a state of active growth. Look for healthy, vigorous stems that are not currently flowering.

Select stems and take cuttings that are approximately 4 to 6 inches long. Remove the leaves from the lower half of each stem to expose the nodes where new roots will form and prevent rot. While not strictly necessary, dipping the cut end into a rooting hormone can accelerate root development.

Plant the prepared cuttings into a pot filled with a well-draining potting mix, as garden soil is often too dense. Insert the cuttings into the soil, ensuring a few of the leafless nodes are buried. Cover the pot with a clear plastic bag to create a humid environment and place it in bright, indirect sunlight.

Caring for New Phlox Plants

For plants propagated by division, the primary focus is on water. Keep the soil consistently moist, but not waterlogged, for the first several weeks after replanting. This consistent moisture helps the roots recover from the stress of division and establish themselves. New foliage growth is a positive sign that the divisions have successfully taken.

For stem cuttings, it will take a few weeks for a sufficient root system to develop. You can check for rooting by giving a cutting a very gentle tug; if you feel resistance, roots have likely formed. Once the cuttings show new growth and have rooted, the plastic bag can be removed. Allow the small plants to grow more robust before transplanting them into their final positions in the garden during a period of mild weather.