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Products > Thunbergia gregorii
Thunbergia gregorii - Orange Clock Vine

Habit and Cultural Information
Category: Vine
Family: Acanthaceae (Acanthus¹)
Origin: Africa, Central (Africa)
Evergreen: Yes
Flower Color: Orange
Bloomtime: Year-round
Synonyms: [Thunbergia gibsonii]
Height: Climbing (Vine)
Width: Spreading
Exposure: Full Sun
Seaside: Yes
Deer Tolerant: Yes
Irrigation (H2O Info): Low Water Needs
Winter Hardiness: 25-30° F
Thunbergia gregorii (Orange Clock Vine) - An evergreen vine that grows to 8-10 ft. tall or if left without support can become an extensive groundcover. The bright, pure orange flowers distinguish it from Thunbergia alata; it blooms year-round in coastal California gardens. Plant in full sun and water only occasionally. This vine is cold hardy to 25 degrees F and will come back from the ground if nipped by a frost. It makes a great chain-link fence climber or a ground cover and it tolerant of near coastal conditions. Thunbergia gregorii comes from tropical Africa, and though similar to its South African relative, the Black-Eyed-Susan Vine (Thunbergia alata), this plant is easily disguisable by its lack of the dark-centered eye of the flower and the wingless petioles. The name for the genus honors the Swedish naturalist Carl Peter Thunberg (1743-1828) who was a student of Linnaeus and spent several years botanizing the Cape of Good Hope. Thunbergia gregorii is considered synonymous with Thunbergia gibsonii and both names were authored by the English botanist Spencer Le Marchant Moore (1850–1931). Moore reportedly named this plant in 1894 to honor his colleague John Walter Gregory (1864-1932), a Scottish explorer and paleontologist. It was on Gregory's travels from 1892-1893 when he explored the Great Rift Valley and collected the type specimen of Thunbergia gregorii. Both names Thunbergia gregorii and T. gibsonii, however, are listed as "unresolved" on The Plant List, the collaborative effort of the Royal Botanic Gardens at Kew and the Missouri Botanic Gardens. We have grown this plant since 1980 and it graces several fence lines in the property.  The information on this page is based on research conducted in our nursery library and from online sources as well as from observations made of this plant as it grows in our nursery, in the nursery's garden and in other gardens that we have observed it in. We also will incorporate comments received from others and always appreciate getting feedback of any kind from those who have additional information, particularly if this information is contrary to what we have written or includes additional cultural tips that might aid others in growing Thunbergia gregorii.