Osteospermum Explained

Osteospermum,^[1] is a genus of flowering plants belonging to the Calenduleae, one of the smaller tribes of the sunflower/daisy family Asteraceae.^[2] They are known as the daisybushes or African daisies.^[3] Its species have been given several common names, including African daisy, South African daisy, Cape daisy and blue-eyed daisy.

Description

Their alternate (rarely opposite) leaves are green, but some variegated forms exist. The leaf form is lanceolate. The leaf margin is entire, but hardy types are toothed.

The daisy-like composite flower consists of disc florets and ray florets, growing singly at the end of branches or sometimes in inflorescences of terminal corymbose cymes. The disc florets are pseudo-bisexual and come in several colors such as blue, yellow and purple. The hardy types usually show a dark blue center in the disc until the yellow pollen is shed. The ray florets are female and are found diverse colors such as white, cream, pink, purple, mauve to yellow. Some cultivars have "spooned" petals such as "Pink Whirls".^[4] Many species flower a second time late summer, stimulated by the cooler night temperatures. Hardy types show profuse flowering in the spring, but they do not get a second flush of flowers.

Taxonomy

The genus Osteospermum was named by Carl Linnaeus in 1753. The scientific name is derived from the Greek osteon (bone) and Latin spermum (seed). Plants of the World Online and the South African National Biodiversity Institute accept a broad definition of the genus, which is a sister taxon to Dimorphotheca. Other authorities treat its generic synonyms (Chrysanthemoides, Oligocarpus, etc.) as separate genera.^[5]

Species

74 species are accepted:

• Osteospermum acanthospermum
• Osteospermum aciphyllum
• Osteospermum afromontanum
• Osteospermum amplectens
• Osteospermum angolense
• Osteospermum apterum
• Osteospermum armatum
• Osteospermum asperulum
• Osteospermum attenuatum
• Osteospermum auriculatum
• Osteospermum australe
• Osteospermum bidens
• Osteospermum bolusii
• Osteospermum breviradiatum — Lemoenboegoe
• Osteospermum burttianum
• Osteospermum calcicola
• Osteospermum calendulaceum — Stinking Roger
• Osteospermum ciliatum
• Osteospermum connatum
• Osteospermum corymbosum
• Osteospermum crassifolium
• Osteospermum dentatum
• Osteospermum elsieae
• Osteospermum grandidentatum — Yellow trailing daisy
• Osteospermum grandiflorum
• Osteospermum hafstroemii
• Osteospermum herbaceum
• Osteospermum hirsutum
• Osteospermum hispidum
• Osteospermum hyoseroides
• Osteospermum ilicifolium
• Osteospermum imbricatum
• Osteospermum incanum
• Osteospermum junceum
• Osteospermum karrooicum
• Osteospermum lanceolatum
• Osteospermum leptolobum
• Osteospermum microcarpum
• Osteospermum microphyllum
• Osteospermum moniliferum
• Osteospermum monocephalum
• Osteospermum monstrosum
• Osteospermum montanum
• Osteospermum muricatum
• Osteospermum namibense
• Osteospermum nervosum
• Osteospermum nordenstamii
• Osteospermum norlindhianum
• Osteospermum nyikense
• Osteospermum oppositifolium
• Osteospermum pinnatilobatum
• Osteospermum pinnatum
• Osteospermum polycephalum
• Osteospermum polygaloides
• Osteospermum potbergense
• Osteospermum pterigoideum
• Osteospermum pyrifolium
• Osteospermum rigidum
• Osteospermum rosulatum
• Osteospermum rotundifolium
• Osteospermum sanctae-helenae
• Osteospermum scariosum
• Osteospermum sinuatum
• Osteospermum spathulatum
• Osteospermum spinescens
• Osteospermum spinigerum
• Osteospermum spinosum
• Osteospermum striatum
• Osteospermum subulatum
• Osteospermum thodei
• Osteospermum tomentosum
• Osteospermum triquetrum
• Osteospermum vaillantii
• Osteospermum volkensii

Formerly placed here

• Dimorphotheca barberae — synonym Osteospermum barberae)
• Dimorphotheca ecklonis — Cape marguerite, blue-and-white daisybush (synonym Osteospermum ecklonis)
• Dimorphotheca fruticosa — Trailing African daisy, shrubby daisybush (synonym Osteospermum fruticosum)
• Dimorphotheca jucunda — South African daisy (synonym Osteospermum jucundum)

Distribution

There are about 70 species native to southern and eastern Africa and the Arabian peninsula.^[6]

Cultivation

Osteospermum are popular in cultivation, where they are frequently used in summer bedding schemes in parks and gardens. Numerous hybrids and cultivars have been grown with a wide range of tropical colors. Yellow cultivars tend to have a yellow center (sometimes off-white).

Plants prefer a warm and sunny position and rich soil, although they tolerate poor soil, salt or drought well. Modern cultivars flower continuously when watered and fertilised well, and dead-heading is not necessary, because they do not set seed easily. If planted in a container, soil should be prevented from drying out completely. If they do, the plants will go into "sleep mode" and survive the period of drought, but they will abort their flower buds and not easily come back into flower. Moreover, roots are relatively susceptible to rotting if watered too profusely after the dry period.

Cultivars

Most widely sold cultivars are grown as annuals, are mainly hybrids of O. jucundum, O. ecklonis and O. grandiflorum and can be hardy to -2 °C (30 °F). If hardy, they can be grown as perennials or as shrubs.

Cultivars (those marked have gained the Royal Horticultural Society's Award of Garden Merit):^[7]

• 'Acapulco'
• 'African Queen'
• 'Apricot'
• 'Biera'
• 'Big Pink'
• 'Blackthorn Seedling' ^[8]
• 'Bodegas Pink'
• 'Buttermilk' ^[9]
• 'Chris Brickell'
• 'Duet'
• 'Giles Gilbey'
• 'Hopleys' ^[10]
• 'Ice White'
• 'Langtrees ^[11]
• 'Lady Leitrim' ^[12]
• 'Lilac Spoon'
• 'Marbella'
• 'Merriments Joy'
• 'Nairobi Purple'
• O. jucundum ^[13]
• 'Passion Mix'
• 'Pink'
• 'Pink Beauty'
• 'Pink Whirls' ^[14]
• 'Silver Sparkler' ^[15]
• 'Soprano'
• 'Starshine'
• 'Springstar Gemma'
• 'Sunkist'
• 'Weetwood' ^[16]
• 'White Pim' ^[17]
• 'White Spoon'
• 'White Whirls'
• 'Whirlygig'

Further reading

• Bussmann, R. W., et al. (2006). Plant use of the Maasai of Sekenani Valley, Maasai Mara, Kenya. J Ethnobiol Ethnomed 2 22.
• Nordenstam, B., and Bremer, Kare (editor). "Tribe Calenduleae" in: Asteraceae: Cladistics and Classification. Portland, Oregon: Timber Press, 1994. . Pp. 365 - 376.

External links

• A phylogenetic study of the Calenduleae - Bertil Nordenstam and Ida Trift
• Osteospermum.com - a website with much information and many photographs
• Sunadora Osteospermums

Notes and References

1. Sunset Western Garden Book, 1995:606–607
2. An interesting new species of Osteospermum (Asteraceae–Calenduleae) from the Western Cape Province, South Africa, providing a link to the genus Chrysanthemoides . Wood . A.R. . Nordenstam . B. . South African Journal of Botany . December 2003 . 572–578 . 69 . 4 . 10.1016/S0254-6299(15)30297-0 . free .
3. Web site: Growing Osteospermum: How To Care For African Daisies . Rhoades . Heather . Gardening Know How . 28 June 2021 . 1 February 2022 . 1 February 2022 . https://web.archive.org/web/20220201225650/https://www.gardeningknowhow.com/ornamental/flowers/african-daisy/african-daisies-osteospermum.htm . live .
4. Book: The Garden . 510 . Royal Horticultural Society . 1997 . 122 . 2022-02-05 . 2022-10-03 . https://web.archive.org/web/20221003045501/https://books.google.com/books?id=l1pMAAAAYAAJ . live .
5. Wessel Swanpoel, Vera de Cauwer and Abraham E. Van Wyk (2020) A new species of Osteospermum subgen. Tripteris (Asteraceae: Calenduleae) from the Namib Desert, Namibia. Phytotaxa 487 (3): 185–194 26 February 2021. https://doi.org/10.11646/phytotaxa.487.3.1
6. Web site: Osteospermum L. . Plants of the World Online . Royal Botanic Gardens, Kew . 2020-07-19 . 2020-08-15 . https://web.archive.org/web/20200815174157/http://www.plantsoftheworldonline.org/taxon/urn:lsid:ipni.org:names:10323-1 . live .
7. Web site: AGM Plants - Ornamental . July 2017 . 70 . Royal Horticultural Society . 14 April 2018 . 5 January 2018 . https://web.archive.org/web/20180105180412/https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-ornamentals.pdf . live .
8. Web site: RHS Plantfinder - Osteospermum 'Blackthorn Seedling' . 14 April 2018 . 17 April 2018 . https://web.archive.org/web/20180417023109/https://www.rhs.org.uk/Plants/49446/i-Osteospermum-jucundum-i-Blackthorn-Seedling/Details . live .
9. Web site: RHS Plant Selector - Osteospermum 'Buttermilk'. 16 January 2021. 28 January 2021. https://web.archive.org/web/20210128052020/https://www.rhs.org.uk/Plants/90573/Osteospermum-Buttermilk/Details. live.
10. Web site: RHS Plant Selector - Osteospermum 'Hopleys'. 16 January 2021. 28 January 2021. https://web.archive.org/web/20210128151646/https://www.rhs.org.uk/Plants/72674/Osteospermum-Hopleys/Details. live.
11. Web site: RHS Plant Selector - Osteospermum jucundum 'Langtrees'. 28 June 2013.
12. Web site: RHS Plantfinder - Osteospermum 'Lady Leitrim'. 14 April 2018. 17 April 2018. https://web.archive.org/web/20180417023451/https://www.rhs.org.uk/Plants/67961/i-Osteospermum-i-Lady-Leitrim/Details. live.
13. Web site: Osteospermum jucundum . RHS . 18 January 2021 . 28 January 2021 . https://web.archive.org/web/20210128031651/https://www.rhs.org.uk/Plants/75740/Osteospermum-jucundum/Details . live .
14. Web site: RHS Plant Selector - Osteospermum 'Pink Whirls'. 16 January 2021. 29 January 2021. https://web.archive.org/web/20210129013440/https://www.rhs.org.uk/Plants/87841/Osteospermum-Pink-Whirls/Details. live.
15. Web site: RHS Plantfinder - Osteospermum 'Silver Sparkler' . 14 April 2018 . 17 April 2018 . https://web.archive.org/web/20180417023659/https://www.rhs.org.uk/Plants/83438/i-Osteospermum-i-Silver-Sparkler-(v)/Details . live .
16. Web site: Osteospermum 'Weetwood' . RHS . 18 January 2021 . 29 January 2021 . https://web.archive.org/web/20210129142332/https://www.rhs.org.uk/Plants/62939/Osteospermum-Weetwood/Details . live .
17. Web site: RHS Plant Selector - Osteospermum 'White Pim'. 16 January 2021. 28 January 2021. https://web.archive.org/web/20210128040244/https://www.rhs.org.uk/Plants/68622/Osteospermum-White-Pim/Details. live.