Stanhopea oculata (purple spot form)

This is a different form of S. oculata that blooms later in the fall than the yellow form that blooms in early summer.  This form has a cream to buff background color on the petals and sepals and also has dark purple spots.  The spots are rather dense on the upper hypochile and there are several dark pink to purple spots near the eye spots on the hypochile as well as on the epichile.  The upper hypochile has a bend that is greater than 90 degrees, but this form does seem to fit into the S. oculata complex.  The upper hypochile is also a deep yellow color.  This form also appreciates warmer and dryer winters than the other forms I have.  It appears to be more of an intermediate grower and grows better with winter night time temperatures between 50.0-60.0°F (10-15.6° C).

Stanhopea oculata (purple spot form) inflorescence.

 

This form has consistently bloomed in fall and begins to push out inflorescences in September.  The flowers are approximately the same size as the other forms up to 4.0 - 4.5 inches (10.2 - 11.4 cm) in diameter.  The fragrance of this form is similar to the yellow form of S. oculata that blooms in early summer with a chocolate peppermint fragrance, though there is a slight infusion of the camphor fragrance that the golden form of S. oculata has.  Altogether this is a good form of this species that extends the bloom season into the fall, and has more color combinations than the other forms. 

Stanhopea oculata (purple spot form) hypochile.

Southland Orchid Show 2013

Two Stanhopea were on exhibit at the show, and the owner Joe Kles of the Riverside/San Bernardino Orchid Society did a great job bringing these species to into bloom again just in time for the show this year.  I am very envious that he was able to get the timing of these to bloom just right since my Stanhopea missed blooming for the show by a week.



Stanhopea graveolens inflorescence

Stanhopea ruckeri flower

In addition to Joe, the Huntington Library, Art Collections, and Botanical Gardens also exhibited several Stanhopeinae.  It was good to see several species in bloom for the show.

Acineta mirayae
 

Acineta superba almost in bloom....very nice! 
 I can't wait until mine has inflorescences this long.

Acineta chrysantha

Acineta is a genus of orchids that is part of the Stanhopeinae, and is native from Mexico to South America.  They are large plants with big pseudobulbs that have 2-4 leaves per pseudobulb.  The inflorescences can be 11.8 to 27.5 inches (30 to 70 cm) long.  This orchid is native to moist cloud forests of Costa Rica, El Salvador, Guatemala, and Panama. It is found at elevations from 4,265 feet (1,300 m), and is a warm to cool growing orchid.  I grow this species outside with Stanhopea on the north facing side of my house in partial shade.



Acineta chrysantha inflorescence

The flowers of this species are waxy and up to 2.5 inches (6 cm) wide.  They open partially and are carried on long inflorescences to 27.5 inches (70 cm) long with up to 30 flowers.  The flowers have a base color of deep or golden yellow with reddish spots on the petals and sepals.  The labellum has large deep red spots and splotches.  The column, in contrast, is ivory white and minutely hairy at the base.  The fragrance of these orchids is rather complex, but ranges more toward a ginger or ginger beer fragrance.  I have heard of this species having a vanilla fragrance, but my variety has a more complex and intense scent.



Acineta chrysantha flower

This orchid has always bloomed for me in late summer and early fall.  The flowers last much longer than most Stanhopea, from two weeks, sometimes up to three weeks if the weather is cool.  The plant requires a cool and semi-dry rest period in early winter to induce blooms.  The first inflorescences grow out of the basket in July and take about 2-3 months to mature and open.

Stanhopea oculata (gold form)

Stanhopea oculata (gold form) inflorescence

This is a different form of Stanhopea oculata that I purchased because it has golden yellow flowers that are more intense than the other forms of the species.  The upper hypochile has a deep golden yellow color and the sepals and petals are a light to golden yellow color. This form also blooms at a later time (late summer/early fall)  than the pale cream to yellow colored form, and it only has two large eyespots on the upper hypochile rather than the four in the pale form. The eyespots and spots on the petals and sepals are a reddish brown color.

Stanhopea oculata (gold form) flower

This form also has a different fragrance that is similar to Eucalyptus, or a little like camphor.  This fragrance tends to align with the 1.8 cineole identified for most S. oculata in a study conducted by Witten and Williams in 1992.  This is a different fragrance than the other form I have that resembles chocolate mint with vanilla.  This is a great form of S. oculata that should be in everyone’s collection.

Stanhopea Fall Culture Checklist

 

As the weather begins to cool, fall is a great time to enjoy Stanhopea blooms and watch new growths emerge.  This is also a good time to repot or rebasket plants because it is still warm and many Stanhopea will continue growth through fall.  By the end of December, most warm growing Stanhopea will complete their growth cycle, and wait for spring/summer to continue growth in preparation for summer or fall bloom.

 

·         Continue watering all Stanhopea regularly and keeping them moist.  I usually water these orchids three to four times a week under normal temperature conditions.  If temperatures rise above 90°F (28°C) and humidity is low I mist and lightly water every day.  Guarding against low humidity is particularly critical growing Stanhopea outdoors in southern California due to the Santa Ana winds we often receive.  These winds are warm to hot and are devoid of humidity.  By the end of fall you can often begin to reduce watering slightly to just two times a week, or less if rainfall is plentiful.

·         Continue fertilizing all species regularly.  I often reduce the manufacturer’s recommendations to one third or one half and fertilize every week, or what is known as weakly-weekly.  Stanhopea can be rather heavy feeders when they are in active growth.

·         Fall is an excellent time to repot smaller Stanhopea or larger baskets.  I usually wait until mid to late October to rebasket because this allows the growths to increase in size and makes it less likely that you will injure them.  This is a prime time for growth for several species and rebasketing is advantageous.

·         Weed baskets to prevent ferns and other plants from taking up space in baskets.

·         In mid fall (November) I remove or roll up most of the saran shade cloth and store it until spring.  This allows the Stanhopea to receive more sunlight, albeit diffused light during the fall and winter months.  This will assist those species that grow all year and often complete their growth in the winter.

·         If you know temperatures are going to increase and humidity levels drop, you may want to consider moving a Stanhopea that is coming into bloom to a shadier more humid area, or as I often do onto my covered patio.  That way I can enjoy the flower show right from my window.  This often prevents early desiccation of flowers and they tend to last the average three to five days instead of just two.

·         Throughout fall make sure to check for growing inflorescences and ensure that their growth is unimpeded by other plants or the basket.  If need be place a plastic label underneath the inflorescence to help direct the growth out of the basket.  Some inflorescences may emerge from the baskets as late as November or December in some species.

·         Use of a methaldihide product or an organic substitute such as Sluggo is advised on a weekly basis at this time to prevent slugs from disfiguring new growth and impacting new inflorescence and bud growth.  I often use a product called “That’s It” that is a granular form and therefore leaves less residue in the growing media.  I am currently testing Sluggo as a more organic method of slug control.

·         Check for spider mites through fall as our weather is still warm and dry.  Small yellow spots on the foliage signal that these pests are active on your Stanhopea.  Spray infected areas with rosemary oil spray or an insecticidal soap to kill the pests as soon as possible to prevent them from damaging the plant further and spreading to other orchids.

·         You should also be diligent in keeping watch for fungus infections at this time on leaves.  Several fungus attack leaves when humidity is high and temperatures are warm. Black or brown spots of leaves and yellowing of leaves in odd patterns are usually the cause of fungus or bacterial infection.  Treat with a fungicide or bactericide.  I often use Physan 20 to deal with the problems and prevent further damage to the plants.

·         The warmer temperatures and reduced breezes combine to cause fungal infections such as black spot on some Stanhopea species and hybrids.  The key to reducing this problem is to make sure your Stanhopea are grown in a breeze way that gets constant air flow, or to place a fan in the growing area that produces a very slight breeze at all times.  This will prevent the fungus from settling on the leaves and disfiguring them.   This problem does not impact the health of the plant to a large degree but it does look unsightly.

Stanhopea tigrina 'SanBar Gold'

S. tigrina var. nigroviolacea 'SanBar Gold'

   

This is another spectacular form of the Mexican species Stanhopea tigrina var. nigroviolacea.  These are the first flowers that have been produced by this plant, but it is a rather vigorous form and produces several growths per year.  I am looking forward to additional inflorescences next year. The flowers have some of the most intense colors of yellow-gold I have seen in this species.  The infusion of gold is most prevalent at the sepal and petal tips and even into the horns.

 

S. tigrina var. nigroviolacea 'SanBar Gold'
showing gold color on back of sepals

The deep gold color is also infused into the back of the petals which makes the flower glow a brilliant golden color.  The back of the petals of the other forms I have are a buff or light yellow in color.  These color combinations make this form a winner in my opinion, especially because of the gold combined with the deep oxblood color of the petals and sepals. 

Stanhopea ruckeri var. alba

This is the form of S. ruckeri that lacks red in the flowers, with no eye spots and no red spots on the petals, sepals, hypochile and column.  The flower is a clean off-white color with green to green blue color infused into the sepals and petals.  The hypochile is a deep yellow color at the base and ivory white on the epichile.  The column is white with a well-defined blue-green infusion of color in the center that is often not captured well in photographs.  Altogether this is a good representative of the crisp and clean color combinations of an alba form of S. ruckeri in sharp contrast to the red spotted form.

S. ruckeri var. alba flowers

S. ruckeri var. alba column with blue-green coloration

 

The fragrance of this flower is very light and almost undetectable.  It favors a slight fresh baked bread scent mixed with lily.   It would seem that this is the form that was given the specific epithet of inodora for its” lack “of fragrance compared with other more fragrant Stanhopea.  This orchid also resembles the plate of S. inodora found in Edward's Botanical Register and published in 1845, from a plant that was imported from Mexico.

Stanhopea stevensonii

This orchid is native to Colombia.  It grows in intermediate to warm mountain forests at approximately 1,312 feet (400-m) in elevation.  This species requires shade and copious amounts of water.  I grow the plant on the north side of my house, and  it appears to need more shade thus it grows better here than with greater sun exposure.  This species has golden yellow flowers with pale red eye spots on the upper hypochile, and few small red spots on the petals and sepals.  There are also small red spots on the epichile and column.  The fragrance of this Stanhopea is difficult to describe and smells sweet but rather chemical-like.  The fragrance is similar to sweet grass with trace amounts of fresh pine needles. Some individuals have described the fragrance as being similar to moth balls, but I have not detected this fragrance in fresh flowers. 

Stanhopea stevensonii inflorescence

 

The flowers are 3.0 to 3.2 inches (7.6 to 8.1 cm) wide with several flowers (5-7) on an inflorescence.   The inflorescences are rather short, to 6 inches (15.2 cm) in length.  This is one of the smaller Stanhopea with short inflorescences, so it is best to grow it in a small basket.  I grow my specimen in an 8 inch (20 cm) basket and it has been doing well in that size basket for years. The leaves of this orchid are a light green, and are 7.5 to 10.5 inches (19 to 26 cm) long and 3.9 to 4.8 inches (10 to 12 cm) wide.  The pseudobulbs are 1.6-2.2 inches (4.0 to 5.6 cm) long and deeply furrowed. 

Stanhopea stevensonii flower

Cirrhaea dependens

This is a small to medium sized orchid that is native to Brazil and found in seasonally dry forests from elevation of 2,297 to 3,937 feet (700 to 1200 m).  The orchid grows in warm locations and requires part shade to prevent the leaves from burning.  It does well in conditions that are similar for growing most Gongora.  The inflorescences are pendulous  1.0 to 1.3 feet (30-40 cm) long, and emerge from the top of the growing medium, so it is best to grow this orchid in baskets.

Cirrhaea dependens flower "dark form"

The flowers are resupinate so even though the inflorescence grows down, the labellum faces up and opens partially.  The flowers can have a green to yellow background with pink to red spots over the petals and sepals.  The form that is in this photograph is the” dark form” with deep maroon markings on the sepals and petals.  The flowers are also short lived similar to Stanhopea and last for only a few days.

Cirrhaea dependens inflorescence
with partially opened flowers

 

 

Stanhopea ruckeri

This orchid is native to Belize, El Salvador, Guatemala, Honduras, Mexico, and Nicaragua.  It grows in intermediate to warm mountain forests 2,625– 4,593 feet (800-1400 m) in elevation.  This is also one of the easiest species of Stanhopea to grow outdoors here in southern California, and can take early morning sun and dappled shade the rest of the day.  The form pictured here is one of the spotted forms with pale red eye spots on the hypochile and small red spots on the petals and sepals.  There are also small red spots on the epichile and column.  There are some forms of this species that are alba forms and lack red color on the flower.  The fragrance of this Stanhopea is a light cinnamon scent and is consistent with the fragrance study done that includes trans-cinnamaldehyde, cinnamyl-alcohol, and cinnamyl-acetate.  These provide a fragrance that is similar to a candy known as “Hot Tamales”, and the flowers have a similar fragrance to the candy.  There are other forms that have different compounds as the main fragrance components such as phenethyl alcohol which provides a sweet to floral, rose fragrance, or even one like freshly baked bread.  It is interesting to note that the form that I have exhibits a change in the fragrance as the flower ages and smells more like cinnamon French toast, so some phenethyl alcohol must be produced at that time as well.



Stanhopea ruckeri with five inflorescences

The flowers are 4.5 to 5.5 inches (11.4 to 14.0 cm) wide with several flowers (5-10) on an inflorescence.   The inflorescences can be quite long, 9 to 15 inches (22.9 to 38.1 cm) in length.  Because the inflorescences are so long, this species can make a very nice specimen placed in a large basket that enables the inflorescences to grow out and down.  The leaves of this orchid are a deep green, and are 7.9 to 24.0 inches (20 to 61 cm) long and 3.9 to 4.7 inches (10 to 12 cm) wide.  The pseudobulbs are 1.6-2.2 inches (4.0 to 5.6 cm) long and deeply furrowed.  This Stanhopea is also one of the more easily grown species and is readily available in the orchid nursery trade.  Stanhopea  ruckeri  grows rapidly, and is a reliable bloomer every year.  It produces several inflorescences at a time and quickly grows into a specimen plant.  These attributes make this Stanhopea a good candidate to grow for a beginner, and several Stanhopea growers rate this species as the one that we should all have.

Stanhopea ruckeri flower

Stanhopea Romp 1 - Andy's Orchids

I was pleased that Andy Phillips from Andy's Orchids agreed to assist me with documenting historical live collections of Stanhopea collected in the wild, and we met at the nursery to discuss this and other research. As always, Andy is a wealth of information on orchids - a real walking encyclopedia.  In between visits from clients I had an opportunity to have a tour of the nursery that is a guided affair.  I had a nice time discussing the trials of Stanhopea cultivation with one of Andy's horticulturalists Katrin.

My favorite place in the nursery is of course "Stanhopea Alley".  Stanhopea are found in many parts of the nursery, but this is the main area for the cool to intermediate growers that can perform well growing outdoors in coastal southern California.

Stanhopea Alley and outdoor growing
 Stanhopea species

In here I found a very nice Stanhopea ruckeri in bloom and bud.  This form has a great cinnamon fragrance and the green tinted column is a nice touch!  I missed the blooming of S. martiana by a few days and the S. oculata that was in spike was a few weeks away.  Several Acineta were also in spike in this area!

Stanhopea ruckeri with a nice cinnamon fragrance

In one of the warm greenhouses I found Acineta superba in bloom, Stanhopea xytriophora in bud (just a day or so away from blooming), and Stanhopea jenischiana 'Catorce' in bud.

Acineta suberba inflorescence

 

Stanhopea xytriophora in bud

 

Stanhopea jenischiana 'Catorce'
inflorescence

 

I had to pinch myself to make sure I was not dreaming.  Katrin took me into another greenhouse to see a Stanhopea that just opened.  I almost could not believe that this was Stanhopea haselowiana.  This was the first time I had the opportunity to see this species in flower - it was fantastic and definitely the highlight to my tour!  Thanks Andy and Kat!



Kat with a nice Stanhopea haselowiana

 

Stanhopea haselowiana flower with intense
purple/red spots in psychedelic patterns.

 

Stanhopea oculata

This species is native to Mexico and Central America (perhaps south to Brazil) from elevations of 3,280-9,842 feet (1000 to 3000 m). It is found in foothill and mountain forests and it grows in intermediate to cool conditions.  This is one of the Stanhopea that can easily grow outdoors in coastal southern California and requires shade and high humidity to perform well. The flowers are moderate sized 4.3-4.5 inches (10.8-11.4 cm) wide, and there are many forms that are buff colored to bright yellow.  There is a considerable amount of variation in color and quantity of spots on the petals and sepals with most having a torus shaped (like the letter O) red to purple colored spots.   Several forms have a plethora of intense red to purple spots on the upper hypochile and the epichile. 

Stanhopea oculata inflorescence

The best known characters used to identify this species is the narrow hypochile that is bent at a 90 degree angle, and several dark red eye spots along the hypochile and base of the petals.  The eye spots are what provide us with the epithet “oculata” meaning eyes in Latin.  The most common form of S. oculata sold in southern California has two eye spots on each side of the hypochile and also two eye spots on each petal.  The inflorescences are up to 25 cm long with 5 to 9 flowers per inflorescence.

Stanhopea oculata flower exhibiting
two eye spots at the base of each petal.

Along with the ease of growth and flowering, and the variable flower color, this species is also well known for its fragrance.  This fragrance has been described as vanilla mixed with mint and a hint of cocoa.  If that fragrance sounds too good to be true, it isn’t, it actually comes close to a chocolate peppermint patty candy scent.  The fragrance rivals that of S. tigrina and can easily fill a room, or be detected twenty feet away in my garden.  This is definitely a species that every Stanhopea grower should have at least one form of!

Stanhopea oculata inflorescence

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 Inflorescences 2013

After our colder than normal winter, spring has been warmer with close to normal temperatures.  This warm and mild weather has increased the speed of the inflorescence growths for early summer, and it appears that the Stanhopea will be blooming on time this year.  Some Stanhopea are producing additional inflorescences this year, and it is always with a sense of satisfaction that the effort you put into growing a good size plant in one year, pays off with more blooms the following year.

As plants continue to mature they should eventually produce additional growths each year that will lead to an increase in inflorescences.  This may take some time to accomplish and patience is definitely a virtue when growing Stanhopea.  For example the S. tigrina var. nigroviolacea ‘Predator’ from my post last year with eight inflorescences produced thirteen this year.  However, two aborted which happens occasionally due to physical damage or a fungal pathogen.  In addition the S. embreei from last year’s post has three flowers on the inflorescence this year with two more inflorescences coming.  It is good to see a plant that I purchased only two years ago continue to grow well and produced more blooms each year.

S.tigrina nigroviolacea 'Predator"
with eleven inflorescences

S. embreei inflorescence with three buds

If you miss the growth of an inflorescence that is at the top of the growing medium and it seems to be attempting to grow back down into the medium, you may want to insert a plastic tag beneath it to help direct it out of the basket.  I have found that allowing an inflorescence that has already surfaced at the top of the growing medium to grow back down will often result in the failure of the inflorescence to mature and bloom.  Approximately 50% of the inflorescences that grow out of the growing medium and then back in, often rot and never bloom for me.

The following will bloom later in the summer and include a different form of S. tigrina var. nigroviolacea that has not bloomed for me before, an S. oculata that refused to bloom last year, and a new inflorescence is emerging on S. intermedia that I am looking forward to seeing for the first time.



S. intermedia emerging inflorescence

 

Stanhopea Diseases

 

Stanhopea are relatively easy to grow and have few problems when cultured properly.  The most bothersome problem I have found is brown spot and anthracnose in some species and hybrids.  I have provided the following partial list of diseases that I have found susceptible by Stanhopea.  However, there are other diseases and viruses that can affect Stanhopea similar to other orchid genera.  I have included a link at the end of the text for further assistance.

Bacteria:

Acidovorax (Pseudomonas) –This starts as a blister that is small, green/brown and eventually enlarges to a brown or black dried and sunken spot.   Bacterial Brown Spot is a water –borne pathogen that thrives in warm and moist conditions.  Increase air circulation and reduce overhead watering.  Spray the plant with a bactericide (e.g., Physan and copper solutions).

Fungus:

Anthracnose (Colletotrichum and Glomeralla ) This fungus affects the leaves and turns the apex brown and then moves to the leaf base.  This often occurs as bands across the leaf, and for me occur often in the early spring with the weather warms and it is still moist.  This is a fungus that is common when air movement is low, temperatures and humidity is high, and light levels are low.  Use a fungicide such as Cleary’s 3336 to prevent further infections.

Black Rot (Phytophthora cactorum and Pythium ultimum) This is a fungus that is present in some orchids and often attacks new leaves and growth.  This infects the vegetation and causes translucent spots and then the tissue dies (necrosis)and turns black in color.  I have not had a problem with black rot on Stanhopea, but rather other orchids in my collection have been susceptible to this fungus.  Removal of the infected plant parts should be accomplished and standing water should be removed in the growing area to reduce infection.  A fungicide such as Cleary’s 336 can be used to prevent further infections.

Botryis is a fungus that often produces brown spots on orchid flowers which are dead cells (necrosis).  The fungus overwinters on dead and rotting vegetation.  Make sure to keep the growing area clear of dead vegetation and lower humidity below 90 percent.  This is not a serious threat to the orchid plant but disfigures the flowers.

Cercospora Leaf Spot (Cercospora spp.) This often begins as a yellow spot under the leaf and then is noticeable on the upper surface.  This infection spreads through the leaf and the spots are sunken and turn black or brown.  Infected leaves fall prematurely. This is a fungus that is common when air movement is low, humidity and moisture on leaves is high.  Use a fungicide such as Cleary’s 3336 to prevent further infections.

Viruses:

Stanhopea ringspot is a virus that causes yellow spots and rings that are circular or diamond shaped on a green leaf background.   The symptoms occur on older leaves or mature leaves.  This virus has been noted on some Stanhopea, though it  is not common.  I have not had much experience with viruses in my collection and tend to keep my growing area clean and ensure that all my tools are disinfected before each use on a different plant.  If you notice that there are signs of virus on your plant, isolate it from the rest of your collections and seek advice from a competent orchid grower.

For further reading see the AOS Orchid Ailments

Stanhopea Summer Culture Checklist

 

The spring season of 2013 was warm and mild.  It has been warmer than the spring of 2012, so this helped the Stanhopea recover from our cold winter.  Due to the warmer and dry spring I have had less problems with fungal and bacteria growth on leaves compared to the rather cool and moist spring from last year.  Even with the warm spring, inflorescence production seems to be approximately two weeks late from last year.  I attribute this late inflorescence growth to our colder than normal winter.  Perhaps this warmer spring/summer weather will allow the orchids to speed up inflorescence growth.

·       Continue watering all Stanhopea regularly and keeping them moist.  I usually water my orchids three to four times a week under normal temperatures.  If temperatures rise above 90°F (28°C) and humidity is low I mist and lightly water every day.

·        Continue fertilizing all species regularly.  I often reduce the manufacturer’s recommendations to one third or one half and fertilize every week,  or what is known as weakly-weekly.  Stanhopea can be rather heavy feeders when they are in active growth.

·         Weed baskets to prevent ferns and other plants from taking up space in baskets.

·        If you grow your Stanhopea  in a sunny area or a greenhouse that receives strong sunlight you may want to place saran shade cloth over the growing area in early spring and summer before the sunlight becomes too strong for them.  You may also want to consider moving the Stanhopea to another shadier growing area for the summer.

·        If you know temperatures are going to increase and humidity levels drop, you may want to consider moving a Stanhopea that is coming into bloom to a shady more humid area, or as I often do onto my covered patio.  That way I can enjoy the flower show right from my window.  This often prevents early desiccation of flowers and they tend to last the average three to five days instead of just two.

·        In late spring/summer make sure to check for growing inflorescences and ensure that their growth is unimpeded by other plants or the basket.  If need be place a plastic label underneath the inflorescence to help direct the growth out of the basket.

·       Use of a methaldihide product or an organic substitute such as "Sluggo" is advised on a weekly basis at this time to prevent slugs from disfiguring new growth and impacting new inflorescence and bud growth.  I often use a product called “That’s It” that is a granular form and therefore leaves less residue in the growing media.  I am currently testing "Sluggo" as a more organic method of slug control.

·        Keep a careful eye out for spider mites as the spring continues and our weather begins to warm and dry out.  Small yellow spots on the foliage signal that these pests are active on your Stanhopea.  Spray infected areas with rosemary oil spray or an insecticidal soap to kill the pests as soon as possible to prevent them from damaging the plant further and spreading to other orchids.

·        You should also be diligent in keeping watch for fungus infections at this time on leaves.  Several fungus attack leaves when humidity is high and temperatures are warm. Black or brown spots of leaves and yellowing of leaves in odd patterns are usually the cause of fungus or bacterial infection.  Treat with a fungicide or bactericide.  I often use Physan 20 to deal with the problems and prevent further damage to the plants.

·        The warmer temperatures and reduced breezes combine to cause fungal infections such as black spot on some Stanhopea species and hybrids.  The key to reducing this problem is to make sure your Stanhopea are grown in a breeze way that gets constant air flow, or to place a fan in the growing area that produces a very slight breeze at all times.  This will prevent the fungus from settling on the leaves and disfiguring them.   The leaf fungal problems do not impact the health of the plant to a large degree but do look unsightly.