Tigrina Trio

I have three forms of S. tigrina var. nigroviolacea blooming at the same time this summer.  The flowering has been exciting because every day another inflorescence opens and more flowers appear, filling the garden with overwhelming fragrance.  The S. tigrina var. nigroviolacea 'Predator' that I have had for over eleven years has produced an inflorescence with three buds for the first time.  The plant has always produced two buds per inflorescence in the past.

Stanhopea tigrina var. nigroviolacea 'Predator'
exhibiting an inflorescence with three buds

 

Once the flowers open, you end up loosing the effect of
having three buds on the inflorescence

 

Two other forms have also produced several inflorescences that may keep the garden filled with S. tigrina blooms for a whole month!

 

Two more forms of Stanhopea tigrina var. nigroviolacea

 



Stanhopea Temperature Requirements

Stanhopea grow well in Tropical and Subtropical climates and many orchid enthusiasts would place them in temperature classifications of intermediate to warm growing.  There are some exceptions and several species tolerate intermediate to cool conditions as well.  Those species that are tolerant of cooler conditions are better suited for growing outside here in southern California due to our cool nights during the winter.  However, most Stanhopea benefit from growing outdoors during the summer and many species are more floriferous when grown outdoors.

There are several temperature classifications for orchids that could apply to the three classes I have described above, however for the uses of growing Stanhopea, I have modified some of these classifications.  The warm classification is primarily 60.0-65.0°F (15.5-18.3°C) average temperatures during winter nights, the intermediate classification is 50.0-60.0°F (10.0-15.5°C) average temperatures during winter nights, and the cool classification is 40.0-50.0°F (4.4-10.0°C) average  temperatures during winter nights.  These classifications are only a general guide for these orchids and some species grow quite comfortably in more than one classification.  Some species such as S. oculata can be found growing well in all three classifications.  This temperature tolerance may be due to the broad distribution of this species and the ability of it to adapt to a wide range of temperature regimes.  Stanhopea oculata successfully grows outdoors in the U.S.in such differing climates as Hawaii, Florida, southern California, and Puerto Rico.  For a complete list of recognized species and temperature requirements see the Stanhopea Temperature Requirements Table 

Here in San Diego my Stanhopeas have been subjected to temperatures as low as 31.0°F (-0.6°C) and as high as 105.0°F (40.6°C).  I expected some damage to the leaves of the Stanhopea plants with the lowest temperature just below freezing, but no long term damage was evident.  Even a few weeks after the light freeze, there did not appear to be any damage to the plants.  One factor that could have assisted the orchids is that I grow many of them under the canopy of trees, and these canopies may have protected them from frost.  The warmest temperatures of 105.0°F (40.6°C) are often accompanied by low humidity and drying winds, so I usually mist or even water the plants daily for the few days in the year when there is excess heat.  Just to clarify, the extreme temperatures listed above were only for brief periods of time, and Stanhopea cannot tolerate extremes in heat or cold for extended periods of time.

The average temperatures in my growing area for winter are 46.0°F (7.8°C) at night and 65.0°F (18.3°C) during the day.  The average summer temperatures in my growing area are a bit higher than San Diego's listed temperatures due to the fact that I live a few miles inland from the ocean.   The average summer temperatures are 65.0°F (18.3°C) at night and 84.5°F (29.2°C) during the day in my  growing area.  These relatively mild conditions are appropriate for growing several of the intermediate to cool tolerant species such as S. oculata, S. tigrina, and S. wardii.  These three species are what I call the “Big Three” of Stanhopea culture because they are easy to grow and relatively easy to obtain from orchid nurseries in my region.  The warm growing species such as the hornless Stanhopeas, S. annulata, S. cirrhata, and S. pulla and the Candida group (S. candida, S. grandiflora, and S. reichenbachiana) require warm temperatures during the winter [nothing below 60.0°F (15.6°C), if only briefly].  These warmer growing species also seem less tolerant of low humidity conditions and tend to exhibit leaf browning as humidity is reduced.

Stanhopea tigrina var. nigroviolacea 'Predator' on left, Stanhopea tigrina var. nigroviolacea center and left

When choosing a Stanhopea to grow, try to ensure that you can provide the best growing conditions that match the natural growing conditions of the species.  For example S. tigrina grows in the mountains west and north of Veracruz at elevations from 1,969 to 5,577 feet (600-1,700 m).  We can learn a great deal about the temperature requirements of a plant by reviewing the climate of the area that it is native to.  This is not a new concept and other growers have eloquently described this in detail.  I have chosen the city of Jalapa, Mexico to demonstrate this concept.  Jalapa is located at an elevation of 4,682 ft (1,427 m) near the upper range of S. tigrina distribution.  Stanhopeas are not native to the city proper but are native to the region surrounding the city, so this provides us with a general idea of what temperatures S. tigrina is subject to (see Table 1 below).  This table provides us with some key pieces of information for growing S. tigrina. First, winter low temperatures range between 52.2-57.6°F (11.2-14.2°C). Second, the two following months in April and May are the warmest months for average high temperatures for the year, and that there is a 19.8-22.3°F (10.5-12.4°C) difference between night and day temperatures known as the diurnal temperature change during the winter months prior to this.  This shift in temperatures appears to have an impact on some Stanhopea species’ ability to increase flower production.  Several growers have had difficulty in blooming Stanhopea species in a more controlled environment (e.g., a greenhouse), but after moving the plants outdoors in spring and summer the plants bloomed more regularly and with more inflorescences. For more information on S. tigrina habitats see Edouard Faria’s blog Stanhopea Passion - Stanhopea tigrina.

Tabel 1. Temperature data for Jalapa, Mexico
Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year Avg.
Average high °F	71.4	73.0	79.9	80.4	82.9	78.4	77.4	78.3	78.3	77.0	74.7	72.7	77.0
Average high° C	21.9	22.8	26.6	26.9	28.3	25.8	25.2	25.7	25.7	25.0	23.7	22.6	25.0
Average low °F	52.5	52.2	57.6	59.9	63.1	61.0	60.6	61.2	61.5	59.4	57.2	54.0	58.3
Average low °C	11.4	11.2	14.2	15.5	17.3	16.1	15.9	16.2	16.4	15.2	14.0	12.2	14.6

Data collected from WorldClimates.com

I grow all of my intermediate to cool growing Stanhopea outdoors throughout the year.  The success I have growing and blooming these species is in large part due to the temperature range of the region I live in, and similarities to the temperatures that species such as S. tigrina experience in nature (see Tables 1 & 2). For example, in my area of San Diego our average winter low temperatures are a little lower than Jalapa at 48.9-52.8°F (9.4-11.6°C), but within the range of temperature variation within the distribution of S. tigrina.  These average winter low temperatures appear to be comfortable for this species and they often continue to grow through January in my area.  This species also performs very well growing outdoors in Santa Barbara, California where the average winter low temperatures are colder 40.3-45.2°F (4.6-7.3°C) (see Table 3).  The winter temperatures in Santa Barbara are cooler than the temperatures in Jalapa, but this adjustment to lower temperatures probably represents temperature tolerance and variability in the species. 

Table 2. Temperature data for San Diego, California
Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year Avg.
Average high °F	65.9	66.5	66.3	68.4	69.1	71.6	76.2	77.8	77.1	74.6	69.9	66.1	70.8
Average high °C	18.8	19.2	19.1	20.2	20.6	21.9	24.5	25.4	25.1	23.6	21.1	18.9	21.6
Average low °F	48.9	50.7	52.8	55.6	59.1	61.9	65.7	67.3	65.6	60.9	53.9	48.8	57.6
Average low °C	9.4	10.4	11.6	13.1	15.1	16.6	18.7	19.6	18.7	16.1	12.2	9.3	14.2

Data collected from climate-zone.com

Table 3. Temperature data for Santa Barbara, California
Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year Avg.
Average high °F	63.7	64.6	65.3	67.4	68.6	71.2	73.9	75.4	75.2	73.1	68.5	64.4	69.3
Average high °C	17.6	18.1	18.5	19.7	20.3	21.7	23.3	24.1	24.0	22.8	20.3	18.0	20.7
Average low °F	40.3	43.2	45.2	47.1	50.1	53.6	56.9	58.2	56.5	51.5	44.7	40.1	49.0
Average low °C	4.6	6.2	7.3	8.4	10.1	12.0	13.8	14.6	13.6	10.8	7.1	4.5	9.4

Data collected from climate-zone.com

The month of April is the first month of inflorescence initiation of S. tigrina in my collection and this coincides with a 13.5-17.0°F (7.5-9.4°C) diurnal temperature change in the winter months prior to initiation.  While these diurnal temperature changes are not as dramatic as those in Jalapa, these appear to be enough to encourage the S. trigrina to be consistent in flower production each year and more floriferous.  This is not to suggest that Stanhopeas cannot be grown in greenhouses and bloom successfully.  Several growers have successfully grown and flowered Stanhopeas in warm conditions.  However, it has been my experience that many Stanhopea including S. tigrina grow better, and are more floriferous growing outside here in southern California  rather than in a greenhouse.  I know of several growers who had difficulties blooming S. tigrina until they moved the plants outdoors.  Barney Greer in his book The Astonishing Stanhopeas provides several examples of species (e.g., S. florida, S. maculosa,  and S. platyceras) that he could not bloom in his greenhouse, but when moved outdoors they began to flower.  Other species of Stanhopea that he grew outdoors as a matter of preference (e.g., S. deltoidea, S. martiana, S. ospinae, S. pozoi, S. tigrina, and S. wardii) and others that grow best in a greenhouse with cool [50.0°F (10.0°C)] night conditions (e.g., S. embreei, S. guttulata, S. hernandezii, S. insignis, S. panamensis, S. posadae, S. ruckeri, S. stevensonii).

If you are having difficulties in blooming some of these Stanhopea you may want to try growing them outdoors if you have the proper climate, or move them outdoors for the summer.  Outdoor diurnal temperature changes between [15.0-20.0°F (8.3-11.1°C)] should provide the proper conditions to initiate flowering.  If you don’t have the option of growing Stanhopeas outdoors, try lowering the temperature of the greenhouse during the night in winter and summer a few degrees, down to 55.0°F (12.7°C) or even 50.0°F (10.0°C), if your other plants can tolerate that treatment, you should have an increased chance in flowering your Stanhopea.  Linda Kraus in her article in the American Orchid Society Bulletin “The Culture of Stanhopeas – Confession of a Requited Love” stresses that she grew her Stanhopeas cool with night temperatures of 52.0°F (11.1°C) even in the summer.  Thus she kept her Stanhopeas in a cool greenhouse condition and they bloomed well.

Printed References:
Greer, B. 1998.  The Astonishing Stanhopeas The Upside-down Orchids. Self Published.

Kraus, L. 1984. The culture of Stanhopeas – “Confessions of a Requited Lover”. AOS Bulletin 53(4): 358-366.

Stanhopea tigrina var. nigroviolacea 'Predator'

S. tigrina var. nigroviolacea 'Predator" with two new flowers opening.

Awesome is an adjective that I like to use to describe this orchid.  It is one of my favorite varieties of Stanhopea that I usually place with S. tigrina var. nigroviolacea.  This orchid has some of the darkest and most intense oxblood, to almost black color on the petals and sepals.  As the grex name implies it is named after a favored cinematic alien invader that hunted humans.  The comparison of the photos here will allow you to make up your own mind…..they do resemble each other to me!

S. tigrina var. nigroviolacea 'Predator' with
four inflorescences open.

This plant is one of my older specimens and I re-basketed it last year.  Since I had purchased it over 10 years ago, it consistently provided me 2 inflorescences each year until last year when it only had one flower.  This year it has rewarded me with nine inflorescences and four have opened all at once.  This orchid has a strong fragrance that is very intense in the cool of the morning until about 11:00 a.m.  A large plant such as this one can produce several inflorescences, and the fragrance of the flowers can be so intense that it can be detected 20 feet away from the plant.  Some people find the fragrance too strong, and almost intoxicating!  The fragrance of these orchids is often described as chocolate and vanilla.  The major component of the fragrance of this orchid and several other Stanhopeas is phenylethyl acetate which can often provide a floral, fruity, or Liqueur-like fragrance.

 

Stanhope tigrina is a sturdy plant for southern California and is not only one of the showiest species in the genus, but is rather easy to grow.  It can often take early morning sun along the coast without burning and dappled shade the rest of the day.  Average fertilizer and water throughout the year are all it demands.  This is one species that can easily be placed in a large basket because the inflorescences can reach over 8 inches in length (20 cm) and can easily grow out of larger baskets.  These orchids produce the largest flowers in the genus and can approach 6 inches (15 cm) in width.  The leaves are tough and leathery 10.0 -12.5 inches (25.4-31.8) cm long and 3.3-4.5 inches (8.3-11.4) cm wide.

Here is another of my attempts at timelaps photography of Stanhopeas.  I was only able to get the last half of these two flowers opening.  It is difficult to get to the flowers before they open in the morning, so I had better be up at 4:00 a.m. for the next chance. 

How do you know your Stanhopea is happy?

 

Stanhopea shuttleworthii in bud

Other than the rather easy answer that your Stanhopea blooms consistently for you every year, there are other signs to observe that can help you understand how well your Stanhopea is growing.  A flowering Stanhopea is usually a content Stanhopea. I have noticed that they will not flower if they are severely stressed or not in the correct environment.  A Stanhopea that consistently produces several inflorescences every year is large enough and being provided the right care in order for it to put a great amount of effort and resources into flowering well.



Stanhopea insignis exhibiting older robust
pseudobulbs and new growth.

A plant that has several new and mature growths is doing well and will have the energy reserves to flower the following year.  A plant that has large pseudobulbs (this varies according to the species) is more likely to produce larger growths and more inflorescences.  Large and firm pseudobulbs are a sign that the plant is doing well.  Some species have folds or wrinkled surfaces such as S. insignis that may look like they are desiccated.  However, if you gently press the pseudobulb between your thumb and index finger and it is firm, then the plant is doing well.  However, if the pseudobulb is spongy or soft, then the plant may be getting either too much or too little water. 




Stanhopea tigrina var. nigroviolacea
producing several inflorescences

Once you have grown your Stanhopea for a few years, you may want to make a trophy plant out of it, re-basket it into a large basket and let it fill the entire container. This will provide you with a massive plant that will produce several if not dozens of inflorescences and bloom for several weeks. These trophy plants are very attractive and show stoppers. However, your orchid cannot remain in the same container forever, and it will eventually decline unless it is divided and re-basketed. Several growers have reported that a Stanhopea that was in decline and not blooming well was invigorated by dividing it and re-basketing the pieces.



Stanhopea gibbosa new root growth

Another sign that a plant is doing well is that it is producing new roots with green growth at the tips, this signifies a growing and elongating root.  The roots should be produced around the base of new pseudobulbs and also throughout the basket. In fact, I usually consider a Stanhopea is doing very well when you can see root growth around the outside edge of the basket.  This signifies that the plant is growing well and producing enough root growth to encompass the entire basket.  This root growth takes advantage of all the water and nutrients in the growing medium every time you water.  Root growth is most evident in the spring and summer months. If roots are not actively growing at this time, you may want to check your plant and make sure that it is receiving the correct amount of water. 

A plant that is not getting enough water will have a growing medium that is dry and the basket will be very light.  Your plant should always be moist, but not sopping wet.  An over dry plant will have roots that will turn gray in color and the roots will begin to die and become desiccated.  If your plant is receiving too much water the roots may not be receiving enough air for gas exchange.  In this last case the media will be soggy and the roots will look very dark brown to black and may be rotting in the anaerobic environment.





Micaela's Stanhopea tigrina var. nigroviolacea

Micaela's Stanhopea tigrina var. nigroviolacea

This form was grown by my friend Micaela from the Riverside-San Bernardino Counties Orchid Society and has two inflorescences on each side of the basket. This plant has bloomed for her for two years in a row. She has to water it quite often in the summer when the temperatures are warm.  It is planted in sphagnum moss and is being grown outdoors under a patio....way to go Micaela!

My form of S. tigrina var. nigroviolacea

Comparing Micaela's form above and mine to the left exhibits a wide array of color variation in this variety . These two forms differ in the amount and intensity of the oxblood coloration on the sepals and petals, and the white and yellow coloration particularly on the hypochile.  This is my form that bloomed last July for the first time in 5 years. I was attempting to grow the plant in a new location and it received too much sun.The leaves were scorched by the end of summer, and I had to rebasket the plant to try to save it. Five years later, it finally forgave the treatment and bloomed again.This year it has two inflorescences growing and is producing four new leaves. 



My form of S. tigrina var. nigroviolacea 
with two flowers


I have learned through trial and error that too much sun and a lack of water will set a mature plant back and prevent a good bloom cycle.  In some cases this will continue for years until the plant is provided with more shade, regular water, and the pseudobulb increases in size enough to allow it to produce an inflorescence.  A life lesson learned….treat your Stanhopeas well and they will reward you!  This is an excellent Stanhopea to grow outdoors in southern California, especially due to the huge 6.7 inch (17 cm) wide flowers and heady vanilla/candy fragrance.