Dendrobiums are among the thousands of orchids on display at the Garden’s annual orchid exhibition.
By Liz Nye, New England Botanic Garden Staff
February 2023
A snowstorm started to ramp up as the horticulturists and gardeners at New England Botanic Garden began a major undertaking—to unload and then unbox an assortment of 2,000 orchid plants that arrived at the receiving dock just that morning. Each tropical plant came wrapped in insulating newspaper and packed alongside dozens of others in large, flat cardboard boxes. With multiple staff on hand, radios at the ready, and dolly carts waiting, the race to get the orchid-filled boxes out of the cold took only minutes. Carefully unwrapping the noodle-like roots and delicate flower spikes of so many orchids—in such an array of shapes and sizes—would be another story.
When sourcing orchids for New England Botanic Garden’s annual orchid exhibition, this year known as Allure, the Horticulture Team can make some requests of the nurseries that grow the plants, but the exact varieties that end up filling the order is always a bit of a surprise. As a result, opening each cardboard box during the unpacking process prompts oohs, ahhs, and often a question: “What orchid is that?”
The answer can be complicated. The plant family Orchidaceae is one of the most numerous on the planet. 28,000 orchid species grow across six continents. So much natural diversity, paired with weak genetic barriers between orchid species makes opportunities for hybridizing this plant practically limitless. And over the last century, ever since a Cornell University botanist discovered a method for easier orchid propagation, commercial growers, scientists, and hobbyists have pushed the bounds, producing upwards of 100,000 hybrids, 61 of which are on display as part of Allure.
With so much diversity, getting to know orchids—“wild” or cultivated—may seem like a daunting undertaking. Here are five “must-knows” that will make this fascinating family of plants a little less of a mystery.
Large whorled pogonia. Photo by Leslie Duthie.
#1: Orchids are everywhere (almost).
Roughly a third of all orchids originate in the tropics. The rest can be found across the globe with species ranging as far north as the Arctic Circle. Distinct adaptations allow different orchid species to thrive in extremely specific geographies, microclimates, and conditions. Orchids from twenty-one different genera can be found in New England. Terrestrial orchids such as the pink lady’s slipper (Cypripedium acaule) and the large whorled pogonia (Isotria verticillata) even make their homes at New England Botanic Garden.
No matter the environment, orchids are entirely dependent on mycorrhizal fungi, fungus that colonizes a plant’s root system, to germinate and develop into mature plants. The symbiotic relationships they form with fungi make propagating or moving naturally occurring orchids, as in the case of conservation efforts, a challenging, even impossible task. Some orchid species are so dependent on a specific species of fungi that conservationists have to preserve fungal spores along with orchid seeds in order to germinate them in the future.
#2. Orchid form follows function—and this gets weird.
Orchids rely on insects, birds, bats, and other animals for pollination. To recruit these pollinators to their causes, orchids have evolved a wide variety of strategies that leverage flower color, pattern, shape, fragrance, and even pheromones. Some tactics are so specialized as to target one single pollinator species alone. While these relationships can be mutually beneficial, often, they are anything but.
Surprisingly, the spider-like look of Brassidium orchids actually help attract a specific pollinator species.
Masters of disguise, many orchids deceive pollinators by mimicking things in the environment that might tempt them. For example, some orchid species evolved a nectar-less flower that looks just like that of the other nectar-full flowering plants it grows among. Others have shapes that signal to certain insects the presence of an appealing habitat or an enjoyable food source, even the promise of a potential mate. The central petal, also known as the labellum, of the bee orchid (Ophrys apifera), resembles a female bee so closely that male bees get tricked into pollinating the orchid in their futile attempts to mate. And orchids of the genus Brassia display flowers that look like giant, leggy spiders to catch the attention of a specific wasp species that seek out large spiders in order to paralyze them and lay eggs on their backs.
#3. Orchid hybrids share family resemblances.
Most orchids we see in stores, exhibits, and homes aren’t naturally occurring orchids, but rather their hybrids—or hybrids of hybrids of hybrids. Despite so much diversity, orchids cultivated from several common groups, or genera, often share recognizable traits. Looking for the hallmarks of these genera in their hybrids can be fun to puzzle out when browsing orchids at a nursey or an exhibition like Allure.
- Brassia (BRASS-ee-ah), a genus commonly called “spider orchids,” displays distinct, arachnid-like flowers. Brassia can be found from Florida to Mexico, the Caribbean, Central America, and South America.
- Dendrobium (den-DRO-bee-um), a genus of roughly 1,500 species that range across tropical and subtropical Asia and Australia, display flowers in a wide variety of colors and sizes. Two round, symmetrical petals unfurl opposite a frilled labellum. The petals alternate with three pointed sepals.
- Some Miltonia (mil-TONE-ee-ah) have spidery, starlike shapes similar to Brassia, but many species and hybrids in this genus have flat, round petals that look like those of a pansy. That’s why these orchids, found from Brazil to northeast Argentina, are commonly called “pansy orchids.”
- Oncidium (on-SID-dee-um) orchids are the famous “dancing ladies.” These orchids, endemic to Central and South America, possess a large, skirt-like labellum. With its two other petals and three sepals, the flower is reminiscent of a person in motion.
- Paphiopedilum (paff-ee-oh-PED-ih-lum), a genus native to Southeast Asia, possess flowers with labellum shaped like buckets that trap insect visitors and then attach pollen grains to them as they make their way out.
- Phalaenopsis (fail-eh-NOP-sis) are some of the most common orchids to encounter in stores. They look similar to Dendrobiums, but instead of pointed sepals, the sepals of Phalaenopsis often look so like petals as to be almost indistinguishable.
#4. Orchids don’t like ice cubes.
Caring for orchids at home is a notoriously challenging business. The plants are finicky, and the care instructions buyers receive can be misleading for first-time growers. For example, contrary to popular belief, no orchid wants ice cubes added to its pot. What many do require is roughly the amount of two ice cube’s worth of water every week. Many orchids also do well with regular misting and plenty of bright, indirect light. But every orchid variety is different. Monitoring an orchid’s roots is one of the best ways to assess its health and figure out what it might need. Luckily, many of the tropical orchid varieties available in stores are epiphytes, species that grow by clinging on to other plants, so their roots are typically exposed. Soft, malleable looking roots are a sign of good health. With the right balance of sunlight, water, and humidity, orchids will put out new leaves and spikes with flowers at least once a year. Or they won’t. Part of indoor orchid care is the practice of patience.
#5. Orchids aren’t invincible.
The orchid hybrids we enjoy today are only possible because such natural diversity exists in the orchid family. But the fascinating plants that first inspired such an explosion of cultivation now face threats from habitat loss and degradation to land fragmentation, climate change, and illegal collection for commercial uses. The highly specialized relationships orchids have with mycorrhizal fungi and pollinators make them especially vulnerable to human-caused changes in their environments. While habitat conservation can be one of the most effective ways to protect specialist species, populations of rare orchids aren’t always easy to locate. Last summer, small whorled pogonia (Isotria medeoloides), a federally threatened species closely related to the Isotria verticillata found at the at the Garden, was found in Vermont. Since 1902, this orchid was believed to be extinct in the region.
Scientists, nonprofit organizations, botanic gardens, community groups, and orchid enthusiasts are working hard to protect orchids in their native habitats. And preservation efforts do find success. You can learn more about this important work through organizations like the North American Orchid Conservation Center, Native Plant Trust, and the Million Orchid Project.
Additional References
Cullina, W. (2004). Understanding orchids: An uncomplicated guide to growing the world’s most exotic plants. Houghton Mifflin.
Liz Nye is the Public Relations Manager at New England Botanic Garden. She holds a master’s degree in science writing from Johns Hopkins University and enjoys learning about and writing about all things plants.