The “citronella plant” sold in garden centers is usually the scented geranium, Pelargonium ‘Citrosum’. This tender perennial cannot survive freezing temperatures. Outside of the warmest climates (USDA Zones 9-11), it is treated as an annual and dies with the first frost. Overwintering the plant indoors preserves specimens, allowing gardeners to enjoy its lemon-scented foliage the following spring.
Bringing the Plant Indoors and Preparing for Winter
The timing for moving the citronella plant inside is crucial and should occur before the first anticipated hard frost. Transition the plant indoors when nighttime temperatures consistently drop below 50°F (10°C). Waiting too long risks permanent damage.
Before the move, the plant needs preparation to ensure it does not bring unwanted pests into the home. Pruning is the first step, reducing the overall size by up to one-half to manage indoor space and conserve energy during semi-dormancy. Cut just above a leaf joint to encourage new growth.
After pruning, thoroughly inspect the plant for common garden pests like whiteflies, aphids, and spider mites. Remove all dead or yellowing foliage, which are common hiding spots for pests and eggs. A forceful spray of water or insecticidal soap helps remove remaining hitchhikers before the plant is brought inside.
Creating the Right Indoor Environment
Once inside, the citronella geranium requires a specific environment to enter a semi-dormant state. The most important factor is light, as these plants thrive on bright conditions. Placing the pot in a sunny, south-facing window is ideal to provide necessary direct light.
If a south-facing window is unavailable, use supplementary artificial grow lights to prevent the plant from stretching out. The ideal overwintering temperature should be cool, maintaining a range between 50°F and 60°F (10°C to 15°C). This cooler temperature encourages a resting period.
Avoid placing the plant near heat vents, radiators, or fireplaces, as direct heat can dry out the foliage. Good airflow is beneficial, even if the plant is not fussy about humidity. Air circulation helps discourage fungal issues like botrytis in enclosed indoor spaces.
Essential Care During the Dormant Months
Caring for the citronella plant during winter requires a significant shift from its summer routine. The most common mistake is overwatering, which quickly leads to root rot in a cool, low-light environment. Watering should be dramatically reduced, only reintroducing moisture when the top inch or two of soil is completely dry.
Since the plant is resting, fertilizing should cease entirely from fall until late winter. Adding fertilizer encourages weak growth that the plant cannot sustain under low winter light. Instead, brush a small amount of fresh potting soil into the pot in late winter to refresh the medium before spring growth begins.
Regular monitoring remains necessary for the reappearance of pests missed during the initial inspection. Dry indoor air can encourage spider mite populations, which should be treated immediately upon detection. Removing any yellowing or dead leaves throughout the winter helps keep the plant clean and maintains good air circulation.
Moving the Plant Back Outside in Spring
The final stage involves transitioning the plant back outside once the risk of cold temperatures has passed. Move the plant outdoors once the danger of frost is gone and nighttime temperatures remain reliably above 50°F (10°C). A sudden shift to the harsh outdoor sun will shock the plant and cause sun scald.
To prevent this damage, a process called “hardening off” is necessary. This gradually reintroduces the plant to full outdoor exposure over 7 to 10 days. Start by placing the pot in a shady, protected spot for a few hours each day, slowly increasing the duration and amount of direct sunlight.
This is the appropriate time to refresh the plant for the upcoming growing season. If the plant became leggy over the winter, prune it back by up to two-thirds to encourage a bushier, compact shape. Repotting or replacing the old soil with fresh, well-draining potting mix provides nutrients for vigorous summer growth.