The plant commonly referred to as a citronella plant is typically the scented geranium, a member of the Pelargonium genus, known for its distinctive lemon-like fragrance when the leaves are crushed. Regular trimming is a simple practice that directly influences the plant’s density, overall appearance, and the intensity of its aroma. Properly pruning your Pelargonium ensures it remains a healthy and vigorous specimen throughout the growing season.
Why Trimming Is Necessary
Without periodic pruning, the plant often develops a “leggy” growth habit, characterized by long, sparse stems that lack foliage at the base. Removing the tips of these stems encourages the plant to branch out laterally, creating a compact, bushy shape. Since the aromatic oils are concentrated in the leaves, a bushier plant produces a greater volume of scented material, maximizing the lemon-like scent. Trimming is also necessary for plant health, allowing for the removal of dead, yellowing, or diseased leaves and stems. Eliminating this debris improves air circulation within the plant’s canopy, which helps prevent fungal issues like gray mold or botrytis blight.
Best Timing for Pruning
Major structural pruning, where you remove a significant portion of the plant, is best performed in the early spring before active growth begins. This allows the plant to direct its energy into producing new shoots and leaves as the weather warms. A secondary, deep trim can also be done in the late summer or early autumn after the main flowering period has finished. Lighter, maintenance trimming, often called “pinching back,” can be done continuously throughout the entire growing season to promote immediate bushiness. For plants brought indoors for the winter, a hard prune, removing up to one-third of the growth, should be completed before the first frost to prepare it for lower light conditions.
Step-by-Step Pruning Guide
Before trimming, ensure your shears or scissors are sharp and clean to make precise cuts that heal quickly and prevent disease entry. For routine maintenance, perform a light prune by pinching or cutting just the soft, new growth at the end of a stem. To encourage branching, the cut must be made just above a leaf node—the small bump on the stem where a leaf or side shoot emerges. This node contains dormant growth buds that will activate once the stem above them is removed. Making the cut approximately a quarter-inch above the node at a slight angle directs water away from the cut surface.
When the plant requires more extensive rejuvenation, a “hard prune” is necessary, removing up to one-third of the plant’s total mass. This deeper cut involves removing older, woodier stems back to a healthy set of leaves or a strong outward-facing node. Always prioritize removing stems that are crossing or growing inward, as well as any that appear damaged or woody without new growth. After trimming, clear away all fallen leaves and stems from the soil surface to maintain a clean environment and discourage disease or pest issues.
Using Cuttings for Propagation
The healthy stems removed during trimming are excellent material for propagating new citronella plants. To prepare a cutting, select a stem section about 4 to 6 inches long with healthy, green growth. Strip away all the lower leaves, leaving only two or three leaves at the very top to reduce moisture loss. The cut end should be placed in a rooting medium, either water or a well-draining soil mix. If using soil, a mixture of perlite and potting mix provides the necessary aeration and drainage.
Dipping the prepared end into a powdered rooting hormone is an optional step that can accelerate root development. When rooting in water, submerge the lower leaf nodes but keep the remaining leaves above the water level, changing the water every few days to keep it fresh. In soil, insert the cutting deep enough so that at least one or two bare nodes are beneath the surface, as this is where roots will emerge. Place the new cuttings in a bright location that receives indirect sunlight; they should begin to form a viable root system within four to six weeks.