Osteospermum/ˌɒstiəˈspɜːrməm,-tioʊ-/,[2][3] is a genus of flowering plants belonging to the Calenduleae, one of the smaller tribes of the sunflower/daisy family Asteraceae.[4] They are known as the daisybushes[5] or African daisies.[6] 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".[7] 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.[1][8]
Dimorphotheca jucunda(E.Phillips) Norl. — South African daisy (synonym Osteospermum jucundumE.Phillips)
Distribution
There are about 70 species native to southern and eastern Africa and the Arabian peninsula.[1]
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.
^USDA, NRCS (n.d.). "Osteospermum". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 26 July 2015.
^The Garden. Vol. 122. Royal Horticultural Society. 1997. p. 510. Archived from the original on 2022-10-03. Retrieved 2022-02-05.
^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
^"AGM Plants - Ornamental"(PDF). Royal Horticultural Society. July 2017. p. 70. Archived(PDF) from the original on 5 January 2018. Retrieved 14 April 2018.
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