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Uncarina grandidieri (Succulent Sesame) - Uncarina grandidieri is a very deciduous plant that can grow upright to 8 to 12 feet tall with heavy stout stems and a trunk that becomes thickened with age and bear near the branch tips soft bright green shallowly five lobes leaves, much like those of cotton (in the unrelated Gossypium genus), that and are finely hairy, sticky to the touch and yield a musty odor when rubbed. These leaves which are held on 2 inch long red and hairy petioles and have red margins when the plant is grown in the sun, often drop completely during winter in our climate. This plant is attractive just in leaf but from spring through summer, sometimes before the leaves emerge, are produced outwardly facing 2 inch wide zygomorphic flowers that are slightly taller than wide with petals a butter yellow surrounding a deep crimson throat that resemble those of a large Petunia or the "Black Eyed Susan Vine" (Thunbergia alata) with the lower petal held nearly horizontal as a landing pad for pollinating insects. Uncarina utilizes a very unique method of pollination. Since the pollen does not shed it involves a pollen eating beetle that lands on the flower to eat the lower part of an anther down in the tube while a sticky glue-like pollen from the upper portion is deposited on its head and then this pollen brushes against the stigma of the next flower entered.
Plant in full to part sun and irrigate occasionally to regularly spring through early fall. It is cold hardy to only around 30 °F so protection from cold is required in winter months in less than frost free zones when irrigation should also be withheld. In our Santa Barbara location we grow this plant very successfully under the eaves of a west facing building so it gets the warmth and protection it needs and not the winter rainfall. This is a great plant for the dry near frost free garden or in container that both dwarfs the plant and also allows it to be moved in for winter protection.
The native habitat of Uncarina grandidieri is the dry forests and xerophytic thickets of south and south-west Madagascar from from Tongobory to Toliara, between Ambovombe and Ifotaka to Amboasary Sud and Fort-Dauphin, Betioky, in the protected areas of Bezŕ Mahafaly (Réserve Spéciale) and Andohahela (Réserve Nationale Intégrale). Because of habitat loss and plant collection this plant has become scarce and in 2013 it came under protection of Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). The name for the genus comes from the Latin word 'uncus' meaning "hook" or "barb" in reference to the hooked spiny fruits. The specific epithet honors Alfred Grandidier (1836-1921), a French naturalist and explorer in Madagascar. We have long called this plant Succulent Sesame as it is in this family, but the fruit is also responsible for the alternative common name Mousetrap Tree. Though not always developing, after flowering, the fruit that can develop is quite interesting and architecturally attractive, but is also best left alone as the small inwardly pointed barbs mounted on 3/4" pedicels will stick to anything. Don't touch this fruit unless you want to spend some time trying to remove it from your fingers (worse than a Chinese finger puzzle!).
Our original stock plant came to us from John Bleck in 1989 and we have sold it at the nursery since 2006.
The information about Uncarina grandidieri displayed on this web page is based on our research conducted in the nursery's horticultural library and from reliable online resources. We also include observations made about it as it grows in our nursery gardens and other gardens we have visited, as well how the crops have performed in containers in our nursery field. We will also incorporate comments we receive from others and welcome hearing from anyone with additional information, particularly if they can share cultural information that would aid others in growing this plant. |
