Pelargonium triste aka Night Scented Pelargonium

Pelargonium triste requires moderate care attention. It thrives with excellent drainage, full sun, and a dry dormancy period during summer. The main challenge is managing its seasonal water needs—keep it moist during the growing season (autumn through spring) but nearly dry during summer dormancy to prevent tuber rot. Once established, it's quite drought-tolerant and forgiving.

Pelargonium triste is celebrated for its exceptional nocturnal fragrance—the species' most distinctive feature. After sunset, the flowers release an intoxicating scent variously described as sweet, musky, cinnamon, or clove-like. This night-scenting evolved to attract long-tongued moths for pollination. The leaves also emit a resinous fragrance when bruised. The plant was historically called 'Geranium indicum Noctu Odoratum' meaning 'Night-scented Indian Geranium'.

Pelargonium triste produces star-shaped flowers from late winter through summer (August to February in its native Southern Hemisphere). The blooms are pale yellow to pale pink with distinctive dark maroon-to-black markings on the petals. Clusters of flowers are held on tall stems above the foliage. While the flowers appear subdued during daylight (hence the name 'triste' meaning dull-coloured), they come alive at night with their remarkable fragrance.

Pelargonium triste is pollinated by nocturnal insects, primarily long-tongued moths. The plant's famous night-time fragrance serves to attract these pollinators in the dark. The tubular flower structure is perfectly designed to receive moths seeking nectar. This evening pollination strategy is relatively unusual among pelargoniums and gives the plant its common name, Night-Scented Pelargonium.

Pelargonium triste can be propagated through three methods: seeds, cuttings, or tuber division. Seeds should be sown in spring at minimum 13°C and typically germinate within 2 weeks. Softwood cuttings are best taken in early summer. The tuberous roots can be divided when the plant is dormant and potted individually. Of these methods, tuber division is often most reliable for maintaining plant characteristics.

Pelargonium triste reaches approximately 0.5 metres (about 20 inches) in both height and spread at maturity. It has a trailing growth habit with finely divided, feathery foliage emerging from ground level. The plant takes 2-5 years to reach its full size. The large underground tuber can develop substantial size over time, serving as the plant's energy storage organ.

Pelargonium triste can only grow outdoors year-round in USDA zones 9-11 or similar mild climates. It's frost-tender and cannot tolerate temperatures below about 0°C (32°F). In cooler climates, grow it in containers that can be moved indoors for winter, or cultivate it under glass year-round. Even in mild areas, ensure excellent drainage to prevent tuber rot.

Pelargonium triste follows a reversed seasonal pattern from most houseplants—it grows actively in autumn through spring and becomes dormant in summer. During the growing season, keep the soil moist but not waterlogged. When temperatures rise and growth slows, reduce watering significantly, keeping the plant nearly dry to prevent tuber rot. In warm climates, it may drop its leaves during summer dormancy, which is completely normal.

Pelargonium triste prefers moderate temperatures and is frost-tender. The minimum temperature it can tolerate is around 0°C (32°F), though it's happiest above 5-10°C (41-50°F). In the UK, RHS classifies it as H1c, meaning it can be grown outdoors in summer but needs protection or glass growing during colder months. Avoid hot, humid conditions which can promote rot.

Pelargonium triste tolerates heavy pruning well. You can cut back the foliage in autumn as the plant enters dormancy, or in spring before new growth begins. Remove spent flower stems after blooming to keep the plant tidy. The plant regenerates readily from its tuberous rootstock, so don't worry about cutting back too hard.

Pelargonium triste is generally disease-free but can be affected by several pests including root mealybugs, thrips, fungus gnats, and glasshouse whitefly. The most significant disease risk is tuber rot caused by overwatering or poor drainage, especially during the dormant period. Ensure excellent drainage and reduce watering when the plant is dormant to prevent this problem.

Pelargonium triste belongs to section Polyactium, subsection Polyactium, which includes seven species that share similar characteristics: substantial underground tubers, evening-scented star-like flowers with pale yellow corollas, and similar cultural requirements. While P. triste itself doesn't have named cultivars, its relatives in this section offer similar appeal for collectors interested in night-scented pelargoniums.

Repot Pelargonium triste during its dormant period in summer, or just before active growth resumes in autumn. Choose containers with excellent drainage holes and use a gritty, well-draining potting mix—sandy soil with added perlite works well. The tuber can be divided during repotting if you wish to propagate. Handle the tuberous roots carefully to avoid damage.

The tuberous roots of Pelargonium triste are edible and can be cooked like potatoes. Starch can also be extracted from the roots. However, edibility is rated only 1 out of 5, indicating it's not a significant food plant. Note that while the tubers are edible for humans, all parts of Pelargonium species are toxic to dogs, cats, and horses.

Pelargonium triste has limited traditional medicinal applications, rated 1 out of 5 for medicinal value. All parts of the plant are astringent, meaning they help reduce secretions and discharges. In South African traditional medicine, infusions from the tannin-rich tubers were used to treat dysentery and diarrhoea. However, it's not considered a major medicinal plant.

Beyond ornamental value, Pelargonium triste has two notable traditional uses. The tannin-rich tubers were historically used in Namaqualand (South Africa) for tanning leather, producing a distinctive reddish-brown colour. The plant also yields essential oils used in perfumery and for scented plant applications, capitalizing on its famous nocturnal fragrance.

Night Scented Pelargonium’s native range is Tropical and Subtropical regions worldwide.

Night Scented Pelargonium should be watered regularly, allowing the soil to dry out between waterings.

Night Scented Pelargonium loves a well-draining soil. Perlite and vermiculite help with drainage, while coco coir adds organic matter, so a good potting soil mix will have all three. You can improve store-bought soil by adding some perlite to it.

Night Scented Pelargonium requires abundant, bright and direct light. Placing it less than one foot from a window is the best way to make sure the plant receives enough light to survive and thrive. Depending on your region, however, the current weather can affect the placement of the plant in your home. For example, in some areas the sun may be too direct and intense, so it's best to place it farther away from the window. You may also need to adjust your placement according to the season as the sunlight can change intensity over the course of the year. If you live in a region with significant temperature fluctuations, such as a desert, you may need to place the plant a bit farther away from the window to avoid extreme heat or cold. With some care and attention, your Rooiwortel will be sure to bring you many years of beauty and enjoyment.

The Night Scented Pelargonium is not in need of supplementary humidity. Most water is taken in by plants through their roots, thus soil watering is the most efficient way to provide humidity to your plants.

The Night Scented Pelargonium should be repotted either when it doubles in size or annually, whichever comes first. Providing new potting soil with all the vital nutrients annually is enough to support the growth of the plant, and thus, there is no need for fertilizer. Remember that plants derive their energy from the sun, not fertilizer.

Ploi's records do not contain confirmed information on the toxicity of this particular plant. In the event of accidental ingestion of plant material with questionable toxicity by you, a family member, or a pet, it is always a good idea to consult a healthcare professional.