The “Mosquito Plant,” often identified as a scented geranium (Pelargonium citrosum or Pelargonium graveolens), is popular for its lemon-citrus fragrance. While its effectiveness as a mosquito deterrent is primarily anecdotal, its ease of care makes it a welcome addition to gardens and patios. Propagating this plant from stem cuttings is the most reliable way to create genetically identical clones. This method allows you to multiply your stock quickly and ensure new plants possess the same desirable characteristics.
Preparing for Propagation
The optimal time to take cuttings is during the plant’s active growth phase, typically late spring through early summer, though cuttings can be taken into the fall. Begin with a healthy, vigorous parent plant free from disease or pests. A day before taking cuttings, ensure the parent plant is well-hydrated by giving it a thorough watering.
Before making any cuts, all tools must be sterilized to prevent the transfer of pathogens that cause stem rot. Use a sharp, clean knife or bypass pruners wiped down with rubbing alcohol or a 10% bleach solution. A sterile, well-draining medium is also necessary, such as a mix of perlite and peat moss or coarse sand, to prevent waterlogging.
Taking the Stem Cuttings
Successful propagation requires selecting semi-hardwood tip cuttings from non-flowering shoots. Take these from the current season’s growth, where the stem is slightly firm at the base but soft at the tip. Aim for cuttings approximately 4 to 6 inches long.
The cut should be made cleanly and diagonally just below a leaf node. This node contains cells capable of developing into new roots. Strip away all lower leaves, leaving only two or three leaves at the top. Removing the lower foliage prevents rotting when buried and reduces water loss through transpiration until roots form.
Some gardeners choose to dip the cut end into rooting hormone powder to stimulate root growth. While Pelargonium species often root easily without it, the hormone can accelerate the process and increase the percentage of successful cuttings. After dipping, gently tap off any excess powder, ensuring the bottom node is well-coated before planting.
Establishing the Root System
The cutting can be rooted in either water or a soil-based medium; the latter is more reliable for long-term health. When using a medium, use a dibber or pencil to create a hole in the moistened mix. Insert the cutting deep enough so that at least one, and preferably two, nodes are covered. Planting into a pre-made hole prevents the rooting hormone from being scraped off.
Rooting cuttings thrive with high humidity and consistent, warm temperatures, ideally between 65°F and 75°F. Place the planted cuttings in bright, indirect light, as intense sunlight can scorch them. To maintain humidity, cover the pots with a clear plastic bag or use a propagation dome.
Monitor the medium closely, keeping it consistently damp but never waterlogged, which can lead to fungal diseases. Roots typically begin to form within four to six weeks. Check for root development by gently tugging on the cutting; resistance indicates the roots have anchored the plant to the medium.
Post-Propagation Care
Once the cuttings have successfully rooted and show new leaf growth, they are ready for transplanting. The young plants should be moved from the propagation medium into individual, slightly larger containers filled with a standard, well-draining potting mix. This transplanting gives the new root system more space and nutrients to expand.
After potting, gradually introduce the plants to brighter conditions, eventually moving them to a location that receives several hours of bright, direct sunlight daily. Proper watering is important during this stage, allowing the top inch of soil to dry out completely between waterings to encourage robust root development and prevent root rot. Wait approximately two weeks after transplanting before beginning a light fertilization schedule with a diluted, balanced liquid fertilizer.