Citronella Plant (Pelargonium Citrosum) – Containers Are A Must For This Tender Plant
Elizabeth is a Permaculture Garden Designer, Sustainability Consultant and Professional Writer, working as an advocate for positive change. She graduated from the University of St. Andrews with an MA in English and Philosophy and obtained a Diploma in Applied Permaculture Design from the Permaculture Association.
Reviewed By COLIN SKELLY
Colin is a Horticulturist and Horticultural Consultant with experience in a range of practical and managerial roles across heritage, commercial and public horticulture. He holds the Royal Horticultural Society’s Master of Horticulture award and has a particular interest in horticultural ecology and naturalistic planting for habitat and climate resilience.
The term ‘citronella’ can be a confusing one, as there are a number of different plants which are referred to by that name.
In this article, we discuss the merits and growing habits of Pelargonium cucullatum subsp. cucullatum, a lemon-scented pelargonium also commonly referred to as Pelargonium citrosum and the ‘Citronella plant’.
This should not be confused with plants in the Citronella genus, nor with lemongrass, which is sometimes referred to as citronella grass.
Overview
| Botanical Name | P. cucullatum subsp. cucullatum |
| Common Name(s) | Citronella Plant; Mosquito Plant |
| Plant Type | Grass / Shrub |
| Native Area | South Africa |
| Hardiness Rating | H1C |
| Foliage | Evergreen |
| Flowers | Pink and purple flowers |
| When To Plant | May – August |
| When To Prune | March – May (or after flowering) |
Sunlight
Preferred
Full Sun
Exposure
Sheltered
Size
Height
1 – 1.5M
Spread
0.1 – 0.5M
Bloom Time
Spring / Summer / Autumn
Soil
Preferred
Chalk, loam or sand
Moisture
Well-drained
pH
Alkaline to neutral
P. cucullatum subsp. cucullatum, also sometimes referred to as the ‘Mosquito Plant’, is an evergreen shrub with a branching habit.
It is well-known for its strong citrus scent and may produce attractive pinkish or purplish flowers sometime between spring and autumn.
Citronella plants can grow to a maximum height of around 1.5m, with a spread of between 0.5-1m.
It can also be kept much smaller and grown in moderately sized containers.
Why Grow Citronella?
Like some other pelargoniums, this is an edible plant.
“Although the correct species name is P. cucullatum ssp. cucullatum, this plant will also be found sold as P. ‘Citronella’ or P. cucullatum,” explains Colin Skelly, a Horticulturist with nearly 15 years of experience.
“There is also a double-flowered cultivar, P. cucculatum ‘Flore Pleno’. It will often be sold and described as a scented leaved Pelargonium with other species and cultivars.”
The scented flowers and leaves can both be eaten in a number of recipes and are used to add a lemony flavour and aroma.
While they may not help to keep insects out of your home, despite the rumours, keeping a citronella plant indoors could bring a pleasing scent to your living spaces.
In the UK, the citronella plant cannot be grown outdoors during the winter, but can be placed outdoors in a warm, sunny spot during the summer months.
Planting
Where To Plant
Citronella plants require a sunny spot and temperatures above 5-10°C.
Over the summer, it can be grown in chalk, loam or sandy soil which is well-drained and has an alkaline or neutral pH in a suitable, sunny spot.
However, since it will not be able to survive outside in the UK when temperatures fall, it is typically grown in containers.
Remember that a container should be filled with a suitably free-draining growing medium, such as a peat-free multipurpose compost with added John Innes (or an equivalent soil-based potting mix), and added grit.
If your citronella plant is being grown in the ground, plants should be lifted in early autumn.
Alternatively, cuttings could be taken in order to have new plants placed the following year.
These plants might also be grown indoors all year round as houseplants.
Remember that these plants like a sunny location, so it is important to make sure when growing indoors, that you place them in as light and bright a spot as possible.
Ideally, these plants should get at least 6 hours of sunlight each day.
Alternatively, they can thrive in a sunny greenhouse that remains reliably frost-free in winter.
When growing indoors or under cover, ensuring adequate ventilation is also important, as these plants require good airflow.
This might involve opening windows or vents in summer and also might mean avoiding crowding too many potted plants on a windowsill or greenhouse staging.
How To Plant
Citronella plants can be purchased online or from a number of plant nurseries.
They are typically purchased as plug plants, or as pot-grown specimens.
They can be planted out in late spring or summer after the last frosts in your area in a suitable spot in your garden, or potted up into suitable containers and placed either outdoors in a suitable location, greenhouse, or on a sunny windowsill.
Spring is the best time to plant houseplants, to ensure the best establishment.
However, you can pot up citronella plants to use as houseplants throughout the year.
Ongoing Plant Care
Watering
Remember that citronella likes free-draining conditions, so it is important to make sure that you do not overwater, and that water can drain freely from the container or through the garden soil in which it is grown.
However, you will need to moderately water your plant when growing indoors or under cover and should not let the growing medium dry out entirely.
Remember that your plants will require more water in the summer, though they still won’t need a huge amount.
Over the winter months, you should water only very sparingly, and make sure that the potting medium has time to dry each time you water.
Outdoors, natural rainfall will usually be sufficient.
The plants are fairly drought tolerant and in the UK, excess rainfall rather than too little rainfall is likely to be more of an issue.
Feeding
Pelargoniums will respond rather well to feeding, so it is a good idea to provide plants in pots with a balanced, organic liquid feed every fortnight through spring.
Then, once the flowers begin to appear, you should switch to a potassium-rich feed, such as comfrey tea or another organic feed, and water with this every couple of weeks throughout the rest of the summer.
Over autumn and winter, reduce feeding to around once a month.
Pruning
Flowers can be deadheaded to promote flowering and the plant can also be given a light trim if required to keep their shape and size in check.
Plants grown outdoors can also be cut back hard in autumn to make it easier to overwinter them indoors.
If you are growing indoors year-round keeping your plants constantly in active growth, it can be a good idea to prune back hard in spring ready for the growth of the new season.
Pests & Problems
Unfortunately, these plants can be susceptible to a range of common problems, especially when grown indoors or under cover.
Aphids, whiteflies, vine weevils, caterpillars, glasshouse leafhoppers and mealybugs can all become an issue.
Check over your plants regularly and consider organic solutions for pest management such as organic pesticides like soap sprays when growing indoors.
Outdoors, encourage natural predation and achieve pest control by creating a wildlife-friendly garden where the ecosystem is in balance.
Fortunately, the citronella plant is not commonly affected by diseases.
Propagation
Citronella plants can be propagated relatively easily by means of softwood cuttings, taken any time between spring and autumn.
Take non-flowering shoots as these will root more easily.
Often, cuttings are taken in spring or early summer and potted up by midsummer when they should have developed reasonably strong root systems.
Later cuttings should only be potted up into their own individual pots the following spring.
As tender plants, Citronellas are not necessarily low-maintenance plants, but for their lemony scent and their flowers, it may be well worthwhile making the effort to grow these plants.
