Publication: J. S. African Bot. 41: 121 1975
Description
Crassula tetragona subsp. connivens is a small erect, succulent shrub with a distinctive silhouette of four-ranked leaves. It is distinguished from the subsp. tetragona by the stems that are papillose when young, becoming thick, fleshy or woody when old. Moreover the plants are comparatively small (200-400 mm tall); the inflorescence is round-topped, almost sessile and usually without bracts. With occasional shearing and shaping it makes a superb succulent bonsai with a thickened trunk covered with peeling parchment-like bark.
Stem: Erect, terete, jointed, repeatedly branched with brown peeling bark, sometimes rooting and hairless.
Leaves: Decussately opposite, concentrated in four ranks at the upper ends of the branches, deciduous, stalkless, 1-5 cm long, 1-4 mm wide, awled, lanceolate, pointed, depressed above subulate obscurely four-cornered, subincurved, spreading, glabrous with small distinct leaf sheaths (1-2 mm long). Leaf color can vary from green to deep, bluish green.
Inflorescence (cyme) Terminal, flat-topped with flowers densely clustered. Young plants of this subspecies resemble plants of subsp. tetragona closely in that they usually develop a distinct peduncle, which is absent or very short in older plants and usually without bracts.
Flowers:Small creamy-white nearly urceolate Sepals 1-2 mm, triangular, blunt; petals 1-3 mm, oblanceolate, elliptic, rounded at tip, ridged on back, but without a projection.. Stamens 1-2 mm, anthers brown. Styles less than one third ovary length.
Booming season: Summer.
Origin and Habitat
Little and Great Karoo, South Africa.
Type locality: Cape, Laingsburg, Ghaap Kop.
Altitude range: 1200 - 2300 metres above sea level.
Habitat: Crassula tetragona subsp. connivens is found on dry northern aspects of hills often in the light shade of small shrubs.
Cultivation and Propagation
Crassula tetragona is a good beginner plant, fast growing, easy to propagate from cuttings and not prone to pests. It grows under a wide variety of climatic conditions provided it is planted in a well-drained situation given adequate water but not over-watered. They are often grown in small bonsai pots and trimmed to appear as pine trees. C. tetragona plants will branch at the tips and can be used as a low, informal hedge.
Growth rate: It is a pretty fast grower.
Soil: Plants grow well in a well-drained mineral soil.
Pots: It needs a relatively shallow pot to accommodate its fibrous roots and provide a very good drainage. It may stay in the same pot for many years.
Watering: It needs moderate water – not too wet nor too dry from autumn to spring with regular water in summer (careful watering required in winter), fairly drought tolerant elsewhere.
Fertilization: Light fertilizer seems to boost its growth whenever additional water is given. Feed it during the growing season with a fertilizer specifically formulated for cactus and succulents (high potash fertilizer with a dilute low nitrogen), including all micro nutrients and trace elements diluted to ½ the strength recommended on the label. It thrive in poor soils and needs a limited supplies of fertilizer to avoid the plant developing excess vegetation, which is easily attacked by fungal diseases.
Special need: Provide very good ventilation. Nearly all problems occur as a result of overwatering and poor ventilation, especially when weather conditions are dull and cool or very humid.
Exposure: It cannot take direct sun in summer but generally needs sun part of the day to bloom. In deep shade it gets pretty weak and leggy and eventually rots and dies. As houseplants, give crassulas up to 6 hours a day of sun.
Pest and diseases: It does not suffer from pests, other than the occasional mealybugs. Protect against frost.
Maintenance: After growing for several years tends to become untidy resulting in thick tops and bare stems at the bottom. Without the pinching and trimming these succulent plants form new branches near the top. To encourage shrubbier growth, pinch off a few leafs at the top or restart it from cuttings.
Uses: These plants are usually used as an ornamental, although they are believed to have been used as a medicinal plant by Thunberg, who wrote: Crassula tetragona, somewhat of an stringent nature, boiled in milk, in the quantity of a handful, is used as a remedy for diarrhoea.”
Hardiness: Outdoors in frost free areas, indoors all other zones
Propagation: Seeds/ Stem cuttings. Sow seeds in autumn. Place cuttings in clean river sand, mist every three to four days, roots should appear within 2-3 weeks.
Bibliography
Major references and further lectures
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Carl Peter Thunberg “Travels at the Cape of Good Hope, 1772-1775: Based on the English Edition London, 1793-1795” Van Riebeeck Society, The, 1986
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George Don, Philip Miller “A General System of Gardening and Botany: Founded Upon Miller’s Gardener’s Dictionary, and Arranged According to the Natural System” Volume 3 C. J. G. and F. Rivington, 1834
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Edgar Lamb, Brian Lamb “The Illustrated Reference on Cacti & Other Succulents” Volume 5 Blandford Press, 1978
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Werner Rauh “The Wonderful World of Succulents: Cultivation and Description of Selected Succulent Plants Other Than Cacti” Smithsonian Institution Press, 1984
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Doreen Court “Succulent Flora of Southern Africa” CRC Press, 01/Jun/2000
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Stuart Max Walters “The European Garden Flora: Dicotyledons” (Part I) Cambridge University Press, 1989
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Gordon D. Rowley “The illustrated encyclopedia of succulents” Crown Publishers, 01/Aug/1978
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Eggli, Urs “Illustrated Handbook of Succulent Plants, Crassulaceae Illustrated Handbook of Succulent Plants.” Springer, Berlin 2002
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Hermann Jacobsen “Abromeitiella to Euphorbia” Blandford Press, 1960
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Hermann Jacobsen “A handbook of succulent plants: descriptions, synonyms, and cultural details for succulents other than Cactaceae” Volume 1 Blandford Press, 1960
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Toelken, H.R. 1997. “A revision of the genus Crassula” in southern Africa. Annals of the Bolus Herbarium 8,1-595.
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Van Jaarsveld, E., Van Wyk, B-E. & Smith, G. “Succulents of South Africa.” Tafelberg, Cape Town. 2000
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John Manning “Field Guide to Fynbos” Struik, 2007
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Vera Higgins “Succulent Plants Illustrated” Blandford Press, 1949
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Goldblatt, P. and Manning, J.C. “Cape Plants: A conspectus of the Cape Flora of South Africa.” Strelitzia 9. National Botanical Institute, Cape Town. 2000.
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Raimondo, D., von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. and Manyama, P.A. “Red List of South African Plants.” Strelitzia 25. South African National Biodiversity Institute, Pretoria. 2009
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Alfred Byrd Graf “Exotica [three] 3: Pictoral Cyclopedia of Exotic Plants” Roehrs, 1963
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Alfred Byrd Graf “Tropica: Color Cyclopedia of Exotic Plants and Trees” Simon & Schuster, 01/giu/1978
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Carl von Linné, Johan Elmgren “A System of Vegetables: According to Their Classes, Orders, Genera, Species, with Their Characters and Differences” in Two Volumes, Volume John Jackson, 1783