Pelargonium incarnatum (L’Her.) Moench.
Common names: ring stork’s-bill (Eng.); horlosie, vrouebossie (Afr.)
This unusual pelargonium definitely has the all the hallmarks of becoming an ornamental hit in fynbos and succulent gardens. It doesn’t need plenty of summer watering.
Prostrate groundcover of approximately 0.2–0.3 m high. Young herbaceous stems possess a green to reddish colour, whereas older woody stems, have a brownish appearance.
The green to reddish leaves are alternately arranged and crowded at the tips of the branches. The lamina varies from trilobate to trifoliolate, cordiform to broadly ovate. The base of the leaf ranges from obtuse to cordate. The peduncle is between 20–70 mm long and covered with fine hairs. The pedicel is 10–40 mm long.
The 5, lanceolate sepals are also finely covered with hairs and 4–6 ×2 mm in size. Five obovate and retuse petals are pale pink with white and deep pink zones and a dark red base. Stamens 5 and 5 staminodes, with the filaments basally fused to form a staminal column of 2 mm long. The ovate ovary is pilose and 5-lobed, with the style 1–2 mm long and the 5 stigmas 1–2 mm long. The bases of the mericarps are 3–4 mm long and the tails are 25–40 mm long.
This species flowers in late spring to mid-summer, from late October to January. The peak flowering period is in early summer, from late November to early December
According to the Red List of South African plants website checked on 7 November 2018, the conservation status of this species is assessed as Least Concern (LC).
Distribution and habitat
This species is confined to a small distribution area from the Kogelberg to Riviersonderend Mountains in the Western Cape, with the Caledon District as the core centre of distribution. This species is prevalent in sandy soils along the southern and eastern sandstone slopes of mountainous areas and is often found under bushes or thick undergrowth. It is also found on gravelly or rocky soils.
Derivation of name and historical aspects
The name Pelargonium is derived from the Greek word pelargos, meaning ‘stork’, because the rostrum of the schizocarp in Pelargonium is thought to resemble the bill of a stork. This explains the common name, stork’s bill. The specific epithet incarnatum, which is Latin meaning ‘flesh pink’, is in reference to the colour of the petals.
The genus Pelargonium is one of 5 genera which constitute the pelargonium family or Geraniaceae. Pelargonium consists of approximately 250 species in southern Africa alone. Geraniaceae is a cosmopolitan family confined to temperate and tropical regions such as S, E and NE Africa, Australia, New Zealand, St Helena, Tristan da Cunha, Madagascar and Asia. Southern Africa, which is home to more than 80% of the species, is regarded as the global hotspot of Pelargonium. The highest diversity amongst members of this family is encountered in the Namaqualand region, and the western and southern Cape of South Africa.
Pelargonium incarnatum was previously classified as Erodium incarnatum and was considered the only indigenous Erodium species in South Africa. All other localized species of Erodium are of an exotic nature and deemed as weeds.
The genus Erodium, known as ‘heron’s bill’, is characterized by 5 free stamens, 5 free staminodes and 5 nectary glands, alternating with the bases of the petals. Most flowers of Erodium species are actinomorphic. Pelargonium incarnatum was initially placed in the genus Erodium based on its actinomorphic flowers and 5 fertile stamens, but this classification became doubtful when further studies revealed findings contrary to it being an Erodium.
Flowers of Pelargonium incarnatum have an actinomorphic appearance, but often 2 of the petals are smaller than the remaining 3. The pollen-producing part of the flower or the androecium is formed by 5 fertile stamens and 5 staminodes. The filaments are fused at the bases and form a staminal column. This staminal column is incongruous to Erodium. An additional outstanding aspect within the floral morphology, was that this species was found to be lacking the nectariferous glands on the receptacle, which is a trademark of Erodium species. Results from pollen studies also indicated that the pollen grains of this species differ from 7 other Erodium species and is instead almost identical to that of Pelargonium tricolor.
A natural hybrid between Pelargonium incarnatum and P. patulum was collected near Grabouw, where the parent species grow together. The corolla of this hybrid possesses the typical colour and markings of P. incarnatum, but the petals were found to be grouped into 2 posterior and 3 anterior ones, resulting in flowers with a zygomorphic appearance. The leaves of this hybrid resemble those of P. patulum. Given the fact that intergeneric hybrids are such a rarity, this discovery of a natural hybrid between P. incarnatum and P. patulum provided the final proof that P. incarnatum belongs in the genus Pelargonium.
This species is placed in the section Campylia which consists of 8 species, and includes Pelargonium elegans, P. ovale, P. tricolor and P. violareum. Species of this group are small with short and erect stems.
The pollination biology of this species is unknown, but it is possible for it to just rely on it its corolla to attract a variety of pollinators.
In the genus Pelargonium the seed or mericarp has a feathered, tail-like structure that is coiled in a spiral arrangement. This tail allows the seed to twist around in the wind and drills itself into the soil. This gives the seed a better chance of germination and ultimately of survival.
No uses or cultural aspects have been recorded to date. This species though has all the potential of becoming an exquisite garden ornamental.
Growing Pelargonium incarnatum
Sow seed in late summer or early autumn in a well-draining medium. Cover the seed lightly with compost or fine sand. Seed will germinate in 2 to 3 weeks. Prick out the seedlings carefully not to damage the roots significantly and pot-up once they have produce 2 or more leaves.
New plants can also be propagated by making use of cuttings. This can be done throughout the year, but the best period is during the active growth phase. Take a cutting of 5–7 cm and remove the leaves and stipules from its lower two thirds. Make a cut below the node, insert in a powder rooting hormone and place in a tray of coarse river sand. Place the cutting-tray in a cold frame in winter or a sheltered spot in summer. Keep the cuttings damp.
The rooting of the cuttings takes 4–6 weeks, after which it can be hardened-off for about 2 weeks. During this period, the rooted cuttings can be fed with liquid Kelpak, which enable root development. Since the roots are very sensitive, care must be taken during the rooting and potting, to minimize any unnecessary form of root disturbance.
As a potplant, do not overwater during the summer months.
Use this species in a rockery, as a pot plant, in mixed plantings (particularly in a fynbos-setup) or border planting. The drainage needs to very good, a period of winter rain and very little water during the summer months.
Companion plants for Pelargonium incarnatum can include: Lampranthus bicolor, Diosma oppositifolia, Ursinia paleacea, Pelargonium capitatum, P. betulinum and P. cucullatum, Protea repens and P. angustifolia, Metalasia densa, Lobelia pinifolia, Monopsis lutea, Serruria phylicoides, Spatalla racemosa, Agathosma imbricata, A. capensis and A. serpyllacea, Edmondia pinifolia, Mimetes cucullatus, Leucadendron platyspermum and Restio festuciformis.
- Bean, A. & Johns, A. 2005. Stellenbosch to Hermanus. South African Wild Flower Guide 5. Botanical Society of South Africa, Cape Town.
- Goldblatt, P. & Manning, J. 2000. Cape Plants. A conspectus of the Cape flora of South Africa. Strelitzia 9. National Botanical Institute, Pretoria & Missouri Botanical Garden, Missouri.
- Oliver, R. 2017-11. Pelargonium tricolor Curtis (Geraniaceae). PlantZAfrica. Internet 5 pp. http://pza.sanbi.org/pelargonium-tricolor
- Stearn, W. 2002. Stearn's dictionary of plant names for gardeners. Timber Press, Portland, Oregon.
- Van der Walt, J J A. 1977. Pelargoniums of South Africa. Purnell, Cape Town.
- Van der Walt, J.J.A., Venter, H.J.T., Verhoeven, R. & Dreyer, L.L. 1990. The transfer of Erodium incarnatum to the genus Pelargonium (Geraniaceae). SouthAfrican Journal of Botany 56(5): 560–564.
Kirstenbosch National Botanical Garden
Plant Type: Ground Cover, Shrub
SA Distribution: Western Cape
Soil type: Sandy, Loam
Flowering season: Spring, Early Summer
Flower colour: Pink
Aspect: Full Sun
Gardening skill: Average