Publication: Aloe 29(1): 15 (1992)
Description
Long known and very popular among succulent fanciers Gasteria carinata var. verrucosa (more commonly known as Gasteria verrucosa) is a peculiar looking plant with two-ranked, dull-green, leaves densely roughened with small, pearly-white excrescences and with grooved upper surfaces. It is probably the best-known example of a Gasteria species with very rough leaves. The name verrucosa, signifies warty or rough. The most popular form has the leaves being completely covered with white tubercles, and in some forms, the tubercles forming ornamental stripes of white bumps over both the ventral and dorsal surfaces. It is one of the most variable species in the genus. Variability includes a very large form (leaves up to 280 mm long) at Infanta (Breede River mouth) and a form with linear, channelled leaves at Herbertsdale.
Habit: It is a small to medium-sized acaulescent succulent. It offsets freely from the base and soon forms a dense cluster with dull green speckled leaves. Dimension of the clumps 3 to 18 cm tall and 15 to 80 cm wide.
Roots: Succulent, up to 6 mm in diameter.
Stem: Stemless.
Rosettes: Distichous with 4-8 (or more) leaves, erect or spreading, remaining distichous even in adulthood. Height 13-15 cm, Spread 13-23cm.
Leaves: Up to15 cm long, 1-5 cm wide at the base, fleshy, triangular-lanceolate, rarely tongue-shaped, leaf apex obtuse or acute. Sheets plane or concave above, with a distinct keel or sometimes rounded below, both faces dull green, tuberculate or smooth, spotted with raised or white domed tubercles scattered or coalescent into transverse rows. Margin cartilaginous, leathery, bearing small inconspicuous rounded teeth, rarely denticulate.
Inflorescence: Raceme, 15-90 cm, unbranched or occasionally with a pair of side branches.
Flowers 2,5-4 cm long, orange-pink and tubular like the usual of this genus, pedicel 7–15 mm long, perianth 16-27 mm long, gasteriform part orange-pink swollen at the base by more than half of the flower length, narrowly ellipsoid to rarely globose-ellipsoid, above constricted into a tube 3-5 mm in diameter.
Blooming season: Winter to late Spring (July to November in the southern hemisphere) but with a peak in spring.
Fruit capsules: 19-23 mm long and 7 mm broad.
Origin and Habitat
South Africa. Endemic to Western Cape (East of Bredasdorp at De Hoop and the Breede River mouth)
Altitude: From close to sea level up to approximately 300 m in altitude above sea level.
Habitat: Hilly terrain, river valley and vertical rock ledges, on shale and sandstone outcrops and occasionally Limestone in dry open fynbos vegetation. It forms large clusters. In case it grows more exposed, it tends to have dark brownish-green colour, but more often they grows hidden amongst bushes and other vegetation, in that case they remains green.
Rainfall: 300–500 mm per annum. Rain occurs in winter and summer but with a tendency to summer dryness.
Temperatures: Summers are hot, with cool nights. Winters are moderate with occasional light frost.
Cultivation and Propagation
Gasteria verrucosa is invaluable for collections as it will tolerate shade. It is of easy culture and can grow on window sills, verandas and in miniature succulent gardens where it is happy to share its habitat with other smaller succulent plants, or in outdoor rockeries. Because of its creeping habit, it makes a nice hanging plant.
Growth rate: It is a relatively slow-growing plant that offsets to form in age small clusters.
Soil: It is tolerant of a wide range of soils and habitats, but prefers a very porous potting mix to increase drainage. You can grow a plant in a 10-15 cm pot for years and have perfectly happy plants. For best results, use a shallow pot.
Exposure: Need light shade to shade, but will take full sun part of the day. (with some sun exposure the leaf develops a nice reddish tint and remain compact)
Watering: During the hot summer months, the soil should be kept moist but not overly wet. During the winter months, water only when the soil becomes completely dry. Wet soil quickly causes root and stem rot, especially during chilly winter months. No water should ever be allowed to stand around the roots. Low ambient humidity is always needed.
Feeding: The plants are fertilized only once during the growing season with a balanced fertilizer diluted to ½ the recommended strength. Plants react well also to organic feeding (compost or any other liquid fertilizer).
Hardiness: During the winter months, water only when the soil becomes completely dry. Frost hardy to -1°C (Or less). It grows well in Mediterranean gardens where frost is not too severe.
Pest and diseases: Rot is only a minor problem with Gasteria if the plants are watered and “aired” correctly. If they are not, fungicides won’t help all that much. Incorrect watering, poor drainage or too much shade can lead to attack by pests and diseases. Care must be given in watering, keeping them warm and wet while growing, and cooler and dry when dormant.
Remarks: Gasterias are best planted in a partially shaded and airy part of the greenhouse, and not too close to the glass roof or sides of the house as the plants can overheat during hot spells.
Propagation: Gasterias are easily propagated by the removal of offshoots or by leaf cuttings in spring or summer. To propagate by leaf cuttings, remove a leaf (best in spring) and let it lie for about one month, giving the wound time to heal. Then lay the leaf on its side with the basal part buried in the soil. This leaf should root within a month or two, and small plants will form at the leaf base. Cuttings are best rooted in clean sand. Once rooted, plants can be planted into individual containers. They can also grown from seed. Sow seed during spring or summer in a warm, shady position in a sandy, slightly acidic soil and keep moist. Cover with a thin layer of sand and keep moist. Germination is usually within 20 days. Seedlings grow slowly and are best planted out about a year after sowing. It is recommended to apply a fungicide when growing it from seed.
Bibliography
Major references and further lectures
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John Robert Brown “Unusual Plants: 110 Spectacular Photographs of Succulents” Abbey Garden Press, 1954
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Van Jaarsveld, E.J. 1994. “Gasterias of South Africa.” Fernwood Press, Cape Town.
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Van Jaarsveld, E.J. 2007.”The genus Gasteria, a synoptic review.” Aloe 44: 4: 84–103.
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Urs Eggli “Illustrated Handbook of Succulent Plants: Monocotyledons” Springer, 2001
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Stuart Max Walters “The European Garden Flora: Pteridophyta, Gymbospermae, Angiospermae-Monocotyledons” Cambridge University Press, 1984
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Mucina, L. & Rutherford, M.C. (eds) 2006. “The vegetation of South Africa, Lesotho and Swaziland.” Strelitzia 19. South African National Biodiversity Institute, Pretoria.
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Doreen Court “Succulent Flora of Southern Africa” CRC Press, 01/giu/2000