ORCHID SPECIES CULTURE
Charles and Margaret Baker

Bifrenaria harrisoniae (Hooker) Rchb. f.

AKA: Dendrobium harrisoniae Hooker, Maxillaria harrisoniae (Hooker)
Lindley, Lycaste harrisoniae (Hooker) B. S. Williams, Colax harrisoniae
Lindley, Maxillaria pubigera Kraenzlin, Maxillaria spathacea Lindley,
Stanhopea harrisoniae G. Don.

ORIGIN/HABITAT: Brazil near Rio De Janeiro. Plants grow on almost
vertical, east facing rock cliffs at 700-2600 ft. (200-800 m). The plants
grow exposed to strong winds and almost full sun with their roots buried
in cracks in the rock face that contain detritus but little in the way of
vegetable matter.

CLIMATE: Station # 83743, Rio De Janeiro, Brazil, Lat. 22.9S, Long. 43.2W,
at an elevation of 89 ft. (27 m). Temperatures are adjusted to a habitat
elevation of 1640 ft. (500 m) resulting in probable extremes of 96.8F
(36.0C) and 40.8F (4.9C).

N/HEMISPHERE    JAN  FEB  MAR  APR  MAY  JUN  JUL  AUG  SEP  OCT  NOV  DEC
F AVG MAX        70   71   70   72   74   77   79   80   78   75   72   71
F AVG MIN        58   59   60   61   63   66   68   68   67   64   61   59
DIURNAL RANGE    12   12   10   11   11   11   11   12   11   11   11   12
RAIN/INCHES     1.6  1.7  2.6  3.1  4.1  5.4  4.9  4.8  5.1  4.2  3.1  2.1
HUMIDITY/%       77   75   78   78   78   78   74   78   81   80   79   78
BLOOM SEASON           *   **  ***  ***    *    *    *
DAYS CLR @ 9AM    9   10    6    7    4    4    6    5    8    5    6    8
RAIN/MM          41   43   66   79  104  137  124  122  130  107   79   53
C AVG MAX      21.0 21.6 21.0 22.2 23.3 24.9 26.0 26.6 25.5 23.8 22.2 21.6
C AVG MIN      14.4 14.9 15.5 16.0 17.2 18.8 19.9 19.9 19.4 17.7 16.0 14.9
DIURNAL RANGE   6.7  6.7  5.6  6.1  6.1  6.1  6.1  6.7  6.1  6.1  6.1  6.7
S/HEMISPHERE    JUL  AUG  SEP  OCT  NOV  DEC  JAN  FEB  MAR  APR  MAY  JUN

Cultural Recommendations:  
The following recommendations are based on averages in the habitat which
should be approximated in cultivation. Reports from growers are included
when they report success with conditions in cultivation that are outside
the range indicated in the habitat.

LIGHT: 3000-4500 fc. Since B. harrisoniae  is normally found growing in
exposed locations on east facing cliffs, full morning sun with afternoon
shading is indicated.

TEMPERATURE: Summer days average 77-80F (25-27C), while nights average
66-68F (19-20C), producing a diurnal range of 10-12F (6-7C).

HUMIDITY: 75-80% throughout the year.

WATER: Moderate water is required during the growing season. Care should
be taken to keep water off the leaves of new growths.

FERTILIZER: A balanced fertilizer mixed at 1/4-1/2 recommended strength
should be applied once a week during periods of active growth. After new
growth is mature, use a fertilizer with less nitrogen and more phosphorus
to allow the new growth to harden before winter and to promote better
blooming the following season. To prevent salt buildup during periods of
heavier fertilizer applications, the pot should be leached or flushed
every month or so. This is accomplished by prewetting the media and then
flushing with water equal to twice the volume of the pot.

REST PERIOD: Winter days average 70-72F (21-22C), while nights average
58-60F (14-16C), producing a diurnal range of 10-12F (6-7C). Along with
the cooler temperatures, water should be reduced to occasional misting or
light watering and fertilizer eliminated for about 2 months in winter.
Gradually resume normal water and fertilizer applications when new growth
starts. Successful growers report that these plants should not be treated
too well in winter. They suggest that water and fertilizer applications be
restricted to every second or third time that Cattleyas are watered and
fed. The pseudobulbs should shrink and even shrivel a bit during the
winter rest. In addition, growers indicate that plants should be placed
high in the greenhouse to receive maximum light. 

GROWING MEDIA: B. harrisoniae  grows well mounted on slabs or rafts if
high humidity can be maintained and sufficient water can be provided.
Medium sized fir bark produces good results for most growers who use pots.
Successful growers suggest that these plants grow well in a potting mix
more like one used for Paphiopedilum than one used with Cattleya. They
further indicate that fir bark with a little coarse sphagnum and some
perlite added produce excellent results. 

MISCELLANEOUS NOTES: Because these plants are intolerant of being
disturbed once established, repotting should be done only when necessary
and then only when new root growth is starting. When dividing, each
division should consist of 4-5 pseudobulbs. Growers report that they have
never found what initiates blooming, and that some plants never bloom.
Whether or not they were providing the conditions indicated above is not
known. 

Plant and Flower Information:

PLANT SIZE AND TYPE: B. harrisoniae  is a medium sized 10-16 in. (25-41
cm) lithophyte that is sometimes found growing as an epiphyte.

PSEUDOBULBS: The clustered, ovoid pseudobulbs are 2.0-3.5 in. (5-9 cm)
tall and often suffused with red-brown, especially near the apex.

LEAVES: The single oblong leaf is 7-12 in. (18-31 cm) long and may be 5
in. (13 cm) wide. It is stiff and upright, leathery in texture, and glossy
dark green.

INFLORESCENCE: Normally 2 per growth, they emerge from the base of the
newest pseudobulbs. They are usually about 2 in. (5 cm) long and bear 1-2
flowers.

FLOWERS: The 2.5-3.0 in. (6-8 cm) flowers are waxy in texture, long
lasting, and are heavily fragrant. The oval-oblong sepals and petals are
spreading with a smaller concave dorsal sepal. Usually white, they may be
yellowish or greenish yellow. The large lip is 3 lobed, hairy, rich
wine-purple to magenta-red with darker veins. 

HYBRIDIZING NOTES: B. harrisoniae  has not been used extensively in
breeding, but it has been successfully crossed with other members of the
subtribe Lycastinae  as well as with allied genera such as Zygopetalum and
Huntleya. 

REFERENCES: 

Associação Orquidofila de São Paulo. 1977. Native orchids of Brasil.
Editora Gráfica Topan-Press Ltda. São Paulo, Brazil. 

Bechtel, H., P. Cribb, and E. Launert. 1980. Manual of cultivated orchid
species. MIT Press, Cambridge, Mass.

Hawkes, A. D. 1987. Encyclopaedia of cultivated orchids. Faber and Faber,
London. 

Pabst, G. F. J. and F. Dungs. 1975. Orchidaceae Brazilienses.
Brücke-Verkag Kurt Schmersow, Hildesheim, Germany. 

Teuscher Henry. 1972. Bifrenaria harrisoniae  and B. inodora. American
Orchid Society Bulletin, Vol 41, No. 11 (Nov. 1972). 

Veitch, James, and Sons. [1887-1894] 1963, 1981. Manual of orchidaceous
plants. Vols. I-II. James Veitch and Sons, Royal Exotic Nursery,  Chelsea,
London. Reprint, Vol. I, A. Asher and Co., Amsterdam, The Netherlands;
reprint, Vol. II, Bishen Singh Mahendra Pal Singh, Dehra Dun, India.


Copyright 1997, Charles O. Baker and Margaret L. Baker
Sheet version 546354

.........................................................................
Please remember that this sheet is for your use only, and though it was
provided free of charge, it may not be reproduced or retransmitted in
any way without permission.
.........................................................................

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 "Orchid Species Culture" Charles & Margaret Baker, Portland, Oregon USA

    Orchid Culture & Pollination site    http://www.orchidculture.com
                     
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