Stanhopea Spring Culture Checklist

 

Winter Wrap Up

The winter of 2013 was particularly difficult for growing Stanhopea.  In January the temperature dipped to 31°F (-0.6°C) for only the second time since I have lived in San Diego.  This low temperature duration was only for a few hours on one night, but it was unusual in that is was part of a 10 night period in which temperatures ranged from 35-39°F (1.7-3.9°C).  This long cold period was particularly difficult for several of the Stanhopea. Some orchids exhibited  bacterial growth presenting a few days after the cold snap along with a loss of  few leaves after several weeks.  In addition to this cold, a very intense hail storm occurred one night and caught me off guard.  Most of my Stanhopea collection is sheltered by trees, roof overhangs, and plastic saran; however, a few plants were partially unprotected during this storm and took some damage.  If I continue to have these tough winters, it will give me incentive to complete the building of a cool greenhouse to protect the orchid collection better by next year.


Stanhopea shuttleworthii growing underneath a tree canopy.  The plant looks good from a distance (left).  However the hail storm damaged the right side of the leaf causing pitting and the cold weather cause bacterial spotting (right)

Stanhopea Spring Culture Checklist

·         Begin watering these species regularly when new growth begins (S. hernandezii, S. insignis, S. jenischiana, S. lietzei, S. maculosa, and S.martiana).

·         Begin fertilizing all species regularly once new growth begins.  I often reduce the manufacturer’s recommendations in 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 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 before the sunlight becomes too strong for them.  You may also want to consider moving the Stanhopea to another shadier growing area.

·         Use of methaldihide products 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 some more organic methods of slug control.

·         In mid to late spring 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.

·         Spring is the second best time to re-pot or re-basket Stanhopea, I think late fall is actually the best time because most Stanhopea have already bloomed and are in a rest period.  It is recommended that you allow new growth to begin before you re-basket so that the growth can mature somewhat before you transplant the orchid.  This will prevent the new growth from being impacted during the process.  Early spring is a good time to transplant because it will also prevent damage to most nascent inflorescences.

·         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 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.

Stanhopea Containers

Stanhopea inflorescences either grow down through the growing media, or along the top of the media and open as a pendent inflorescence.   Therefore, it is highly recommended to grow Stanhopea in a basket.  There are some individuals who have been successful in blooming Stanhopea grown in plastic pots with holes in the bottom.  However, as the plant grows larger, and the inflorescences increase in size, it becomes more difficult for the inflorescences to make their way out of the pot and the inflorescences often die.  Some fortunate individuals have been able to successfully grow and bloom Stanhopea mounted on wood, cork, or wood rafts when the growing conditions provided are moist and humid at all times.  However, here in southern California where our summers are rainless and humidity is low, baskets seem to work best for growing Stanhopea. For seedlings and small plants, I grow these in 2-4 inch (5-10 cm) plastic pots before they can be transferred to a 6 inch (15 cm) basket.

Stanhopea embreei inflorescence emerging from a plastic basket (left).  Stanhopea shuttleworthii
 inflorescences emerging from a plastic basket (right). Note that I had to remove the top rim of the
 basket to allow for the maturation of the upper inflorescences.  The Stanhopea on the right is
 definitely due for re-basketing.

 

You may be asking what kind of basket is best for growing Stanhopea?  A basket that is durable and strong is a good start, and most Stanhopea grow best in baskets that are either 6-12 inches (15-30 cm) in diameter.  Larger baskets can be used if you want to create a specimen plant.  The baskets should be approximately 5-6 inches (13-15 cm) deep to allow the inflorescences a chance to grow completely through the growing media.  In some species (e.g., S. trigrina and S. wardii) the inflorescences grow longer and these can accommodate deeper baskets up to 8-10 inches(20-25 cm) in depth.  There are a variety of baskets on the market that are sufficient for growing Stanhopea.  These include polyethylene plastic, wire or metal, and wood slat baskets.  I have also seen Stanhopea grown in ceramic baskets, netted bags, and in almost any container that has holes large enough to allow the inflorescences to mature and grow out of the basket.  I will discuss each of the three main types of baskets mentioned above and their advantages and disadvantages.

Plastic baskets are relatively inexpensive, durable, lightweight, and can be stored and transported easily.  As my Stanhopea collection has grown, I have chosen this type of basket over the others because of the cost, however these are not the most ornamental of the baskets.  These baskets can be obtained in sizes that range from 4-12 inches (10-30 cm) in diameter.  I usually choose the 6 inch (15 cm) size as the minimum due to my dry environment, because this size basket dries out much less frequently than smaller baskets.  Most of my smaller Stanhopea are placed in plastic baskets until they can be transferred to a larger wire baskets later.  The holes in the plastic baskets are approximately ½ -1 inch (1.3-2.5 cm) in diameter and are sufficient in size to allow the inflorescences to pass through. One issue with plastic baskets is that as the Stanhopea grow larger, they will often send new pseudobulb shoots through the holes in the basket.  Once this growth elongates through the holes and matures, one must cut the plant out of the container when it is time to re-basket.  This situation can often lead to a frustrating time when re-basketing and an increased chance of damaging the plant.

Plastic baskets in the 8-10 inch (20-25 cm) sizes (left). Stanhopea oculata growing in an 8 inch (20 cm) basket (center).  An example of a Stanhopea gibbosa pseudobulb that has grown through the side of the basket (right).

Wire and metal baskets are more expensive, very durable, and rather lightweight.  I choose to grow my larger Stanhopea in these baskets which can vary in size from 10-18 inches (25-45 cm) wide.  These baskets have an improved aesthetic quality and the larger spaces in between the wire allow the inflorescences to easily pass though.  I also choose this type of basket to grow the larger specimen size Stanhopea.  This is because wire baskets allow the pseudobulbs to grow around the edges and sides so that the plant can be grown in the basket for longer periods of time, usually 3-4 years before re-basketing.  The durability of these baskets is good and they can often last for a decade before being replaced.  When re-basketing it is much easier to break apart the stems around a wire basket than a plastic one.  I have several Stanhopea that I grow in 12 inch (30 cm) wire baskets that are flattened on one side to allowing them to be hung on walls and flat surfaces.  I have chosen this type of basket to facilitate the expansion of my collection and use of a preponderance of wall and flat space to exhibit the collection.  The downside to this type of basket is that Stanhopea will often grow the inflorescence toward the back of the basket and wall.  I usually turn the basket around temporarily to allow the inflorescence to grow and bloom normally.  I can usually avoid most of the backward growing inflorescences when re-basketing by ensuring that the new lead growth is pointing toward the front of the basket.

Stanhope oculata in a 12 inch (30 cm) basket that I have grown for over 12 years (left).  Newly divided Stanhopea florida in a 12 inch (30 cm) flat basket growing on lattice (right)

I think wood baskets are one of the most ornamental of the choices, but are expensive and bulky.  The baskets are often available in teak and fir with 8-12 inch (20-30 cm) size widths, and have ½ inch (1.3 cm) slatted openings on the side, and 2 inch (5 cm) openings on the bottom that allow the inflorescences to pass though.  These baskets are strong and long lasting, but are rather heavy and not easy to transport.  The thickness of the wood slats can inhibit inflorescence growth, so an attentive eye is necessary to ensure that the inflorescences are allowed to grow between the slats.  I have several Stanhopea that are growing in visually important areas in my yard where I grow them in wood baskets for high impact and ornamental character.

Coryhopea hybrid growing in a 12 inch (30 cm) fir basket on my patio (right).  Stanhopea candida growing in a 10 inch
(25 cm) fir basket that is kept warm by growing in my bathroom over winter (right).