Interview: The Orchid Doctor 2014-09-03T23:43:02+00:00

Q&A with the Orchid Doctor, Dennis Westler

© Ingrid Taylar, for


Dennis Westler, the Orchid Doctor, is a horticultural specialist who fields orchid queries at the San Francisco Orchid Society’s website. He helps orchid growers from around the world tackle a diverse range of plant-related issues. He’s also the organizer of the annual Pacific Orchid Exposition in San Francisco, this year held from March 5 to March 8 at Fort Mason’s Festival Pavilion. I had the opportunity to ask Mr. Westler a few questions about orchids, their cultivation, and about this year’s expo theme: “Green … With Envy.”

What originally drew you to the study of orchids?

I should mention that although I am called the Orchid Doctor, my educational experience is in natural resources, land use planning, and landscape architecture. As an orchidist I am an autodidact. I started doing “Orchid Doctoring” at our shows, at meetings and in private consultation when I realized I enjoyed the problem-solving aspect, and was good at teaching techniques.

I started growing orchids in 1974, at the height of the houseplant craze. Having been through most of the common houseplants I wanted a challenge. I saw a Phalaenopsis amabilis (the great granddaddy of the big, elegant, white hybrids) and fell in love. Because I had studied plant physiology and forest ecology in college, the extreme form and adaptation of both the plant and the flowers really appealed to me.

Although people often kill their first orchids, I did well with it, blooming it every year till the late 80s when I gave it away. That plant started me acquiring more, buying books, asking questions, visiting habitat and so on.

To what do you attribute the public’s fascination with orchids?

Several things really. The mystique for one: the fact that for so long they were the flower of the rich and royal. The exoticness — that they come from far off, tropic places. Most people are not familiar with their native orchids. Their beauty, and for those who get hooked, the weird and bizarre ones. Then there is the fact that they are seen so much in advertising and in home and garden magazines. They have come to represent good taste. And more and more, it’s the same things that attracted me.

This year we celebrate the bicentenary of Darwin’s birth. Can you tell me a bit about how Darwin’s studies influenced scientific understanding of these plants?

Darwin, in fact, wrote an entire book of his observations on both temperate zone orchids, and the ones that he saw in the tropics, focusing specifically on pollination mechanisms.

One of the most important things that Darwin realized about the orchids was the co-evolution of flower and pollinating insect, and the pollinator specificity of orchids. In many cases only one species of insect can pollinate a specific orchid. And that flower is often irresistibly alluring to that insect.

The famous example was Darwin’s statement — after studying the Madagascan Angraecum sesquipedale — that a moth must exist with a tongue as long as the enormous nectar spur of the flower (up to 18 inches). Entomologists scoffed, but 40 years later the moth was found, just as Darwin predicted. He was fascinated by the apparent pollination strategies of orchids, and many people still are. The orchids’ use of sexual attractants, deception, and traps of various sorts is amazing.

One example of this is the various ladyslippers which trap insects like a pitcher plant. There is only one avenue of escape which forces the insect to either pick up pollen or deposit pollen picked up previously. Another example is the European Ophrys. It has a lip that resembles a female wasp or bee, and actually produces the same pheromone that the female would. They are irresistibly attractive to the males who pollinate the flower by pseudocopulation. Our docent tours at the Orchid Exposition point out flowers with unusual pollination strategies.

Is there anything to suggest orchids have developed or are developing adaptive strategies to deal with stresses such as reduced numbers of their specific pollinators?

Generally, these things occur too quickly for natural selection to be of much good. If there is another species that occasionally pollinates the plant successfully, the species has a chance to adapt. Or if the species exhibits cleistogamy (auto-pollination achieved by the flower without an insect visit), it may also persist and adapt to other available pollinators. Generally though, when an orchid’s pollinator disappears, so does the orchid, at least locally.

What are the most common mistakes people make when trying to grow orchids? And, are there any orchid absolutes? Or is the care of an orchid entirely species dependent?

The most common mistakes people make when growing orchids are not giving them enough light, and not watering them properly (overwatering, or mistakes in watering technique). Not repotting properly or frequently enough runs a close third. After that, is a failure to understand temperature requirements.

The only absolute is that care of the root system is paramount in growing healthy orchids. The care that individual species, or related groups of hybrids require (in terms of temperature, light, watering frequency, and dormancy) varies wildly within the family. Among the orchids commonly grown, for example, the temperature range some require to grow and bloom would kill others.

Is there anyone who shouldn’t try to grow an orchid? That is, is orchid cultivation better suited to certain qualities or personalities?

Clearly, there are people with no interest in plant husbandry. I think they would just find orchid growing frustrating. Among people who enjoy caring for plants, I think there is an orchid to fit every temperament — providing you have the right light, and the desire to learn. There are even those orchids that literally thrive on neglect. The genus Eulophia comes to mind. Some of the Eulophia species grow in deserts, and are usually seen in Cactus and succulent collections rather than orchid collections. The perfect orchid for some people. Cattleya is another genus that works well for people who don’t like to fuss and don’t water frequently.

Are some orchids closer to your heart than others?

A difficult question to answer. Often the orchids closest to my heart are the ones in bloom at the moment.

I am a big fan of the Lady Slippers. They are simple vegetatively, but the flowers are complex and bizarre in their colors and patterns. I love the Masdevallias because many of them grow easily outdoors in the Bay Area. They are often very brightly colored, and the uninitiated find them distinctly unorchid-like.

Then there are the Pterostylis, an Australian group that grow in soil, from tubers. The flowers are green and white and brown and very odd (the common name is “greenhoods”). What I really like about them is that they have an irritable lip that traps their pollinator using the same kind of cellular mechanism a venus flytrap uses to close its leaf trap. Of course, after the insect struggles long enough to pick up the pollen, the lip relaxes and lets the insect go.

I also love the Pleiones, deciduous orchids with gorgeous flowers that spring up before the leaves. They are kind of like cherry blossoms to me, an intense beauty made poignant by their brevity. Unlike many orchids they only last a week to 10 days.

I read that orchids can grow on every continent but Antarctica — and that they are native to all states. Which species are native to the San Francisco Bay Area? Where can people find them?

Probably the most spectacular native orchid in these parts is Calypso bulbosa. These bloom in March and April and are found most often in association with stands of Redwood or Douglas Fir. They have one leaf that hugs the ground and the flower spikes stand about three inches tall. The flowers are about an inch or so with bright orchid pink to purple petals and sepals, the lip is shaped like a slipper and is richly colored in white with bronzy orange, and deep purplish stripes inside. The common name is “fairy slipper” or “Venus’ Slipper” . Probably the best place to see them is on Mount Tamalpais. They can be found along the Cataract Trail, some years in great numbers. Unfortunately this plant has never been successfully transplanted or nursery grown from seed.

Growing in the same area will be Goodyera oblongifolia, the western rattlesnake plantain. This is a summer flowering orchid with little white flowers, but the foliage is evergreen and very beautiful, a rich green with white mottling around the midvein.

You can also find the Coralroots (Corallorhiza) blooming in mid-to-late April. These are saprophytic orchids. They live on rotting organic matter in association with specific fungus, have no chlorophyll, and never produce leaves. The only growth that they produce above ground is their flowers which are on thin, eight-to-twelve-inch-long stems and look sort of like tiny Cymbidiums in shades of brown and white. These are often seen on the Sawyer Camp Trail by Crystal Springs Reservoir.

One can also find Spiranthes and Piperia species in the Bay Area, but they are not as showy. Our prolonged dry season here in California gives us a smaller number of orchid species than some other parts of the country.

What advice would you give to an orchid novice attending a show like the Pacific Orchid Exposition? And if purchasing an orchid, which species should they consider?

I encourage novices to take their time and let all the variety and beauty sink in. Write down the names of plants that interest you: the complete name, because the part in quotes (the clone name) is meaningless without all the rest — genus, and species or grex (hybrid) name. I also encourage novices to come to the Orchid Doctor desk and take a tour of the show, or ask questions. Plan on spending a few hours, there is a lot to see.

There are really few specific species to consider, as genus is the more important thing. And often a hybrid will be easier for a beginner, as hybrids tend to be more forgiving. Most people feel beginners should start with Phalaenopsis or Paphiopedilums, but some will do better with a Cattleya or Dendrobium. If you have space outdoors with good light, Cymbidiums are great for beginners.

In purchasing an orchid you want to try growing and reblooming, you should be prepared to accurately describe your conditions to a vendor: your available light, the temperature range in your house, whether you like to water or not, that sort of thing. I feel that one of the best ways to enjoy orchid growing is to find the plants best suited to your temperament and to your conditions.

This year, the Pacific Orchid Exposition highlights environmental preservation. How will the 2009 exposition differ from previous expos in terms of this particular focus?

We have encouraged our exhibitors to provide information in their displays about what they do to keep their businesses or hobby green — and what we all can do. We expect a great deal more informational content about orchids this year than in the past. So the show will be as beautiful as it has ever been, but richer in educational content. At my Orchid Doctor desk I will be distributing information about organizations that are on the forefront of orchid preservation. Most notably, the Orchid Conservation Alliance and Orchid Conservation Coalition.

What are the greatest threats to orchid conservation worldwide?

By far the greatest threat to the survival of orchid species is habitat loss. This is both in the tropic and here in the temperate zones as well. There are cases where collection and smuggling of choice new species has stripped them from specific locales, but these, though well publicized, are few and far between. Cutting and burning of forests, draining of wetlands, conversion of forest to farmland, the growth of suburbs — all uncontrolled and without oversight — these are driving orchid (and other) species to extinction.

Because of the pollinator specificity I mentioned above, loss of insects as a result of encroaching farming and the use of agricultural chemicals can drive an orchid to extinction, even if its immediate habitat remains untouched. Populations also move about through time, as the texture of the forest or grasslands changes. So there are complex interactions that have to be taken into account before land is developed. And when land is preserved, the parcels need to be large enough or linked in some way.

In terms of orchid cultivation commercially, how widespread is usage of pesticides or other potentially harmful chemicals?

It is important to note here that even the most dangerous of pesticides can be applied properly and responsibly in a greenhouse, and pose little or no threat to the environment. Because of the public expectation of a cosmetic product, fungicides and pesticides are used as necessary. These are certainly “potentially harmful chemicals.”

I think few commercial growers use pesticides preventively these days, but many do use fungicides to prevent infection. Although no one wants to buy a plant with toxic residue, they don’t want a plant with aphids or leaf spots either. Commercial growers cannot use things like insecticidal soap because of the cost, labor intensive application, and potential for damage to flowers and foliage. The irony is that the products less toxic to us are more toxic to the plants, especially the flowers.

What growers can do (and most do) is apply pesticides as infrequently as possible, and in as responsible a manner as possible. Frequent inspection, spot treatment rather than blanket sprays, maintaining optimal conditions to maximize resistance to illness, are all ways growers minimize their need for pesticides.

What environmentally-friendly growing methods are available to both private and commercial growers? And is there global momentum in this direction?

Among other things:

  1. The use of fertilizers produced from renewable resources (products that are organic based rather than derived from fossil fuels).

  2. The use of sustainable potting materials (coconut coir and chunks as opposed to fir bark or most tree fern).

  3. Reuse and recycling of pots.

  4. Growing more regionally appropriate genera to reduce the energy cost of heating and cooling greenhouses.

  5. Double and triple glazed greenhouses to also reduce energy use.

  6. Passive solar methods used to heat greenhouse.

  7. Certainly in the home or hobby greenhouse where sprays are less likely to be contained, less toxic products should be used.

  8. Species orchids should be grown from seed rather than collected and imported. There are community based growers in the tropics now using profits from species sales to preserve and protect the jungle, as well as provide services for indigenous communities.

There will be information about this available at the show. These things have to be market driven really, other than the legislation that has reduced trade in wild collected species. But these are definitely trends, and more and more growers are following these trends.

Is there any other orchid advice you’d like to give — any question that never gets asked which deserves an answer nonetheless?

This is something I mention in talks I give, which is kind of blasphemous to some people. If you have no place to grow orchids it is okay to use them as temporary pot plants in your home just as people do with hydrangeas and azaleas. The plants you see sold in many stores are often grown specifically to be enjoyed and tossed. Like a pot of lilies purchased at the supermarket, they often will not perform well in the long term. If you are looking for plants to grow and enjoy for years, shows like ours are the perfect opportunity to find them. Specialty growers are producing plants to be kept and loved, and they are grown with love.

What are some of your most memorable comments, questions or experiences in the context of being the Orchid Doctor?

I answer a lot of questions, and on the website they come from folks all over the world. What I really like is when someone comes back to me and tells me that their plants are doing better for them, or something they had not been able to flower is now flowering. I enjoy knowing that my advice has increased someone’s results and satisfaction. That is memorable to me.

What I dislike is when someone has not put any effort into describing their plant or their problem and wants advice nonetheless. They don’t have the name of the plant, don’t have an image to show me, cannot describe it or the conditions under which it grows and so on. It is like going to the doctor and when asked what the problem is saying “I don’t feel well”, or “you’re the doctor, you tell me”. That is frustrating to me. Diagnosis of orchid issues, even if the plant is present is often a give and take, I need to know what the person has done in the past.


You can find the Orchid Doctor at this weekend’s Pacific Orchid Exposition. The event happens from March 5 to March 8, 2009. Find additional details, schedule and ticket prices at the event website.