AFRICAN

ORCHIDS

Read more of Cultivation of Sobennikoffia robusta (Schltr.) Schltr.,
Light:
3000-4500 fc. Light should be filtered or diffused, and plants should not be exposed to direct midday sun. Strong air movement should be provided at all times.
Temperatures:
Summer days average 68-70F (20-21C), and nights average 56F (13C), with a diurnal range of 12-15F (7-8C). Plants should thrive if grown in the cool, moist air from an evaporative cooler during particularly hot weather. Hillerman & Holst (1986) reported that plants grow very well with intermediate conditions but suggested they may grow even better with warmer temperatures. Plants will probably adapt to daytime temperatures somewhat warmer than indicated in the preceding climate table if air movement is strong and if they are able to cool down at night. We suggest that growing under significantly warmer conditions should be approached slowly and carefully, however.
Humidity:
80-85% in summer and early autumn. Averages than drop quickly in late autumn to 60-65% in winter and early spring before increasing again rather quickly the following spring.
Water:
Rainfall in the region is very heavy from late spring to early autumn. Averages then drop quickly into a 5- to 6-month dry season that extends from midautumn to early in the following spring. Cultivated plants should be watered heavily while actively growing, but drainage must be excellent, and conditions around the roots should never be allowed to become stale or soggy.
Fertilizer:
1/4-1/2 recommended strength, applied weekly when plants are actively growing. Many growers prefer to use a balanced fertilizer throughout the year; but others use a high-nitrogen fertilizer from spring to midsummer, then switch to one high in phosphates in late summer and autumn.
Rest period:
Winter days average 67-69F (19-21C), and nights average 49-50F (9-10C), with a diurnal range of 18-20F (10-11C). Rainfall in the region is low in winter, but some additional moisture may be available from heavy dew. Water should be reduced for cultivated plants from late autumn into the following spring, but they should not be left completely without water for long periods. Occasional early morning mistings between very infrequent light waterings should provide sufficient moisture in most growing areas. Water should be increased somewhat what if the leaves wrinkle excessively or show other signs of stress. Fertilizer should be greatly reduced or eliminated until heavier watering is resumed in spring.
Growing media:
Plants may be grown in shallow, well-drained containers or mounted on tree-fern slabs. Mounted plants need high humidity, however, and during hot, dry weather they may need several waterings a day. If it is difficult to keep mounted plants moist enough, they may be grown in a shallow pot or basket filled with a very open, fast-draining medium that has excellent drainage, is well aerated, and allows the medium to dry fairly rapidly after watering. Growers generally use medium-sized fir bark or shredded tree-fern fiber and add varying amounts of chunky perlite and/or chopped sphagnum moss to keep the medium open and retain some moisture. Including charcoal in the mix also holds the medium open and prevents souring in the pot. Plants should be repotted immediately if the medium starts to break down or whenever the plant outgrows its container. Repotting should be done just as new roots start to grow. This enables the plant to become reestablished in the shortest possible time. Hillerman & Holst (1986) suggested using pots that are 5-8 in. (13-20 cm) in diameter or mounting on slabs that are at least 4 by 12 in. (12 by 30 cm) in size.
Notes:
Growers report that plants bloom for a long time, and cultivation records show blooming from late spring to late summer.
References:
This information is quoted from a Charles and Margaret Baker culture sheet, with permission from Troy Meyers This email address is being protected from spambots. You need JavaScript enabled to view it.. The entire culture sheet can be obtained by subscription from Orchid Species Culture, http://orchidculture.com











Read more of Cultivation of Sobennikoffia humbertiana H.Perrier,
Light:
2500-3500 fc. Light should be filtered or diffused, and plants should not be exposed to direct midday sun. Strong air movement should be provided at all times.
Temperatures:
Summer days average 85-86F (29-30C), and nights average 65-66F (18-19C), with a diurnal range of 20-21F (11-12C).
Humidity:
70-75% in summer and autumn, dropping to 60-65% for about 3 months in late winter and early spring.
Water:
Rainfall is moderate to heavy from late spring to early autumn. Averages then drop rather abruptly in midautumn at the beginning of the dry season, that lasts about 5 months until late winter or early spring. Cultivated plants should be watered heavily while actively growing, but drainage must be excellent. Water should be reduced in autumn after new growths mature.
Fertilizer:
1/4-1/2 recommended strength, applied weekly when plants are actively growing. Many growers prefer to use a balanced fertilizer throughout the year; but others use a high-nitrogen fertilizer from spring to midsummer, then switch to one high in phosphates in late summer and autumn.
Rest period:
Winter days average 75-78F (24-26C), and nights average 53-54F (12C), with a diurnal range of 22-25F (12-14C). Rainfall in the habitat is low from autumn to early spring. Humidity remains relatively high throughout the year, however, so considerable additional moisture is available from heavy dew and late-night mist. Cultivated plants need much less water in winter, but plants should not be completely without water for long periods. Occasional early-morning mistings between infrequent light waterings should be adequate in most growing areas. Water should be increased somewhat if leaves shrivel or show signs of stress. Fertilizer should be eliminated until new growth starts and heavier watering is resumed in spring. Hillerman and Holst (1986) reported that, "It is accustomed to a long dry spell, and probably should be given a dry rest period, although we have not found this to be necessary for flowering. We water weekly for pots, daily for slabs."
Growing media:
Plants may be grown in shallow, well-drained containers or mounted on tree-fern slabs. Mounted plants need high humidity, however, and during hot, dry weather they may need several waterings a day. If it is difficult to keep mounted plants moist enough, they may be grown in a shallow pot or basket filled with a very open, fast-draining medium that has excellent drainage, is well aerated, and allows the medium to dry fairly rapidly after watering. Growers generally use medium-sized fir bark or shredded tree-fern fiber and add varying amounts of chunky perlite and/or chopped sphagnum moss to keep the medium open and retain some moisture. Including charcoal in the mix also holds the medium open and prevents souring in the pot. Plants should be repotted immediately if the medium starts to break down or whenever the plant outgrows its container. Repotting should be done just as new roots start to grow. This enables the plant to become reestablished in the shortest possible time. Hillerman & Holst (1986) suggested using pots that are 5-8 in. (13-20 cm) in diameter or mounting on slabs that are at least 4 by 12 in. (12 by 30 cm) in size.
Notes:
Growers report that plants are in bloom for an extended time.
References:
This information is quoted from a Charles and Margaret Baker culture sheet, with permission from Troy Meyers This email address is being protected from spambots. You need JavaScript enabled to view it.. The entire culture sheet can be obtained by subscription from Orchid Species Culture, http://orchidculture.com











Sobennikoffia poissoniana H.Perrier, Notul. Syst. (Paris) 14: 164 (1951).
Description:
Plant small, with a very short stem. Leaves few, ligulate, narrowing at the base to resemble a petiole, 5-10 cm long, 1.7 cm wide. Inflorescence 9 cm long, few-flowered; bracts deltoid, obtuse, 3.5 cm long. Flowers white; sepals oblong, attenuate or acute at the apex; lateral sepals somewhat dilated on the internal margin; petals shorter than the sepals, slightly dilated on the lower margin; lip 3-lobed, the lobes rounded, 5 mm wide, lip in total 2-2.3 cm long; spur cylindrical, 15-17 mm long.
Habitat:
Epiphyte or lithophyte in coastal vegetation; near sea level; flowering November to December.
Cultivation:
As given for the genus.
Distribution:
N. & NW. Madagascar
References:
WCSP (2017). 'World Checklist of Selected Plant Families. 15.03.2017; http://apps.kew.org/wcsp/
Images:
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                  In culture                   In culture
sobennikoffia poissoniana 01 sobennikoffia poissoniana 02
Photograph ©Leo Klemm. Image used with kind permission. Photograph ©Leo Klemm. Image used with kind permission.













Sobennikoffia robusta (Schltr.) Schltr., Repert. Spec. Nov. Regni Veg. Beih. 33: 362 (1925).
Homotypic Synonyms:
Oeonia robusta Schltr., Ann. Inst. Bot.-Géol. Colon. Marseille, III, 1: 184 (1913).
Angraecum robustum (Schltr.) Schltr., Beih. Bot. Centralbl. 33(2): 427 (1915).
Description:
A robust epiphyte or lithophyte that grows to more than 16 in. (40 cm) tall. Numerous roots that are very long, white with green tips, often aerial, and 0.2 in. (0.4-0.6 cm) in diameter are produced. Pseudobulb/stem: Old plants may have stems that do not commonly branch and are 10-16 in. (25-40 cm) long by 0.4-0.6 in. (1.0-1.5 cm) in diameter. The lower portion of the stem is covered with brown leaf sheaths. Leaves: 10-15 in. (25-38 cm) long by 1.0-1.4 in. (2.5-3.5 cm) wide. Numerous very leathery, strap-shaped leaves with unevenly and bluntly bilobed tips are carried on the stem. The leaves, which are not glossy, are colored a medium green, have wavy margins, are fairly strongly ribbed, and are slightly to moderately keeled on the back. Inflorescence: Up to 20 in. (50 cm) long, with an upright, rigid peduncle that is clad with several sheaths and is about 0.1 in. (0.3 cm) in diameter. Flowers are carried in a loose cluster, each with a floral bract that is oval, bluntly pointed, and much longer than the up to 1.2 in. (3 cm) long pedicel. Flowers: 12-17 per inflorescence. The flowers, which are white but turn yellowish with age, are about 2.4 in. (6 cm) across and 2 in. (5 cm) tall and have sepals and petals that are recurved, especially at their tips. Sepals are lanceolate-elliptical with sharply pointed tips. The dorsal sepals is up to 1.4 in. (3.5 cm) long by 0.6 in. (1.4 cm) wide near the base. The curved, sickle-shaped lateral sepals are up to 1.6 in. (4 cm) long by 0.4 in. (1.1 cm) wide. The broadly sickle-shaped petals s are sharply pointed, more or less horizontally spreading, have sharply pointed tips, and measure up to 1.4 in. (3.5 cm) long by 0.5 in. (1.3 cm) wide near the base. The 3-lobed lip is concave but does not embrace the column. It is up to 1.8 in. (4.5 cm) long by 1 in. (2.5 cm) wide. The center lobe is 0.6 in. (1.5 cm) long, while the two outer lobes are about 0.4 in. (1 cm) long. The rear portion of the lip forms a wide spur which turns upward and is about 1.8-2.0 in. (4.5-5.0 cm) long. The spur is about 0.3 in. (0.8 cm) broad at the entrance but tapers rather sharply to about 0.08 in. (0.2 cm) wide within a distance of about 0.6 in. (1.5 cm) of the entrance. The column is tall with rather square earlike appendages.
Habitat:
This orchid is found in the western portion on the island where it has been found near Mahajanga at 4900-6550 ft. (1500-2000 m). It grows on or at the foot of trees and shrubs in woody areas with sandy soil in a region where there is a significant dry season. Plants usually are epiphytic or lithophytic, but they may occasionally be found growing as terrestrials.
Cultivation:
Read more of Cultivation of Sobennikoffia robusta (Schltr.) Schltr.,
Notes:
While not a small plant, Sobennikoffia robusta is certainly no giant Angraecum eburneum type, and is comparable to medium-sized cattleyas. This little known species deserves a place in every good collection. It blooms in late May and early June, and its well-arranged flowers form spectacular sprays, with 2 or 3 inflorescences per plant. The sepals and petals of the showy flowers are gracefully recurved. The flowers are white with a slight greenish tint on the back sides as well as on the midrib of each segment. The spur is quite greenish, as is the throat of the flower. As they age, the flowers turn a rich apricot color, which may be maintained for several weeks. This color also appears when the flower is pollinated. These green “cool white” flowers, which last at least one month, are immediate eye catchers, and prove to be conversation pieces at any showing. Add to this picture a subdued spicy scent in the evening hours, and you have a sure award-winner. Long blooming and frequent blooming orchid species.
Distribution:
W. Madagascar
References:
De la Bathie, H., and H. Humbert. [1939, 1941] 1981. Flora of Madagascar 1-2. The Government of Madagascar and the National Museum of Natural History, Paris. Translated and published in 1 vol., Steven D. Beckman, 621 Palm Ave., Lodi, CA, U.S.A. 95240. Du Puy, D., P. Cribb, J. Bosser, and J. and C. Hermans. 1999. The Orchids of Madagascar. The Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, England. Hamilton, R. 1988. When does it flower? 2nd ed. Robert M. Hamilton, 9211 Beckwith Road, Richmond, B. C., Canada V6X 1V7. Hillerman, F. and A. Holst. 1986. An introduction to the cultivated Angraecoid orchids of Madagascar. Timber Press, Portland, Ore. 'World Checklist of Selected Plant Families. 15.03.2017; http://apps.kew.org/wcsp/
Images:
Click on each image to see a larger version.

            In culture           In culture           In culture             In culture
Sobbenikofia robusta 01 Sobbenikofia robusta 03 Sobennikoffia robusta 02 Sobennikoffia robusta 04
Photograph© Lourens Grobler. Image used with kind permission. Photograph© Lourens Grobler. Image used with kind permission. Photograph© Lourens Grobler. Image used with kind permission. Photograph© Lourens Grobler. Image used with kind permission.

Sobennikoffia humbertiana H.Perrier, Notul. Syst. (Paris) 7: 134 (1938).
Description:
A rather large plant with growths up to 20 in. (50 cm) tall. Numerous roots up to 0.3 in. (0.8 cm) in diameter are produce along the stem to within about 6 in. (15 cm) of its apex. Pseudobulb/stem: 16-20 in. (40-50 cm) long by 0.4-0.6 in. (1.0-1.5 cm) in diameter.Leaves: 6-10 in. (15-25 cm) long by 0.8-1.0 in. (2.0-2.5 cm) wide. Usually 11-15 long-lasting, strap-shaped leaves are carried toward the apex of the stem. They are leathery, have bluntly pointed and unequally bilobed tips, and have margins that are slightly wavy, particularly on older plants. Inflorescence: 12-16 in. (30-40 cm) long, including the 4 in. (9-11 cm) long peduncle, by 0.1-0.2 in. (0.3-0.4 cm) in diameter. The long, arching flower spike emerges from the axil of the leaf sheaths. Flowers are carried in a raceme with a wavy rachis and are spaced about 1.2 in. (3 cm) apart at the lower end of the rachis but become closer together, about 1.0 in. (2.5 cm) apart, toward the tip. The floral bracts are very bluntly pointed, very wide, and 0.2-0.3 in. (0.6-0.7 cm) long, and each blossom is carried on a pedicel that is about 1.4 in. (3.5 cm) long and hold the flowers out at a 45 angle from the rachis. Flowers: 5-8 per inflorescence. The spreading flowers are white when young but become yellowish with age, have sepals with a strong green tint on the back, and have green in the throat of the lip. They are about 1.6 in. (4 cm) across, with sepals and petals that average 0.8 in. (2 cm) long by 0.4 in. (1 cm) wide and are very gracefully recurved in the apical 0.3 in. (0.7 cm). The 3-lobed lip is about 1 in. (2.5 cm) long by 0.6 in. (1.5 cm) wide and has a spur at its base that is about 1 in. (2.5 cm) long. The very thick column is about 0.1 in. (0.3 cm) long.
Habitat:
This orchid is found mainly in the central-southern part of the island where it grows among rocks, mostly in dry forests, at 1300-3950 ft. (400-1200 m). Plants may be found in humid evergreen forest or in dry scrubland, however. The areas where this orchid is found experience a distinct, long dry season when most of the moisture comes from early-morning dew and occasional mist.
Cultivation:
Read more of Cultivation of Sobennikoffia humbertiana H.Perrier,
Notes:
Sobennikoffia humbertiana is a spectacular plant when in full flower. Although it is flot small, neither can it be considered excessively large, and its floral display is well worth the space it takes. It is a reliable bloomer, and growing seems to offer no problems. The fragrance of the flowers is very spicy and pleasing. Flowering occurs in April and May, and the blooms last moderately well. As the flowers age, they turn an apricot color, which is maintained for 10—14 days. A well-grown plant should carry 3— 5 30- to 40-cm inflorescences, each with 9—14 flowers. The spurs are quite unique for angraecoids in that they turn up instead of down. Since the plant branches freely at the base and the branches are well-rooted, exporters frequently break up old adult plants prior to shipping, and in these “new” divisions the leaves may be much smaller. This species is definitely a “sleeper” in the hobby and will undoubtedly become very popular once it becomes readily available.
Distribution:
SC. & SW. Madagascar
References:
De la Bathie, H., and H. Humbert. [1939, 1941] 1981. Flora of Madagascar 1-2. The Government of Madagascar and the National Museum of Natural History, Paris. Translated and published in 1 vol., Steven D. Beckman, 621 Palm Ave., Lodi, CA, U.S.A. 95240. Du Puy, D., P. Cribb, J. Bosser, J. and C. Hermans. 1999. The Orchids of Madagascar. The Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, England. Hillerman, F. and A. Holst. 1986. An introduction to the cultivated Angraecoid orchids of Madagascar. Timber Press, Portland, Ore. Yearron, S. H. Nov. 17, 1999. Long blooming and frequent blooming orchid species. WCSP (2017). 'World Checklist of Selected Plant Families. 15.03.2017; http://apps.kew.org/wcsp/
Images:
Click on each image to see a larger version.

         Habitat/In situ          Habitat/In situ              In culture
Sobennikoffia humbertiana 01 Sobennikoffia humbertianna 02 Sobbenikofia humbertiana 01
Photograph ©Gilles Grunenwald. Image used with kind permission. Photograph ©Gilles Grunenwald. Image used with kind permission. Photograph© Lourens Grobler. Image used with kind permission.