Fascinating Flora

Carnivorous plants make for clever fly catchers
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The Venus flytrap is probably the best known meat-eating plant thanks to Hollywood, but don’t worry, we have yet to find one big enough to catch a human.

Retired pathologist George Newman is a man with many interests. A passionate plantsman and photographer, he has hiked all the 4,000 footers in New Hampshire, and he has traveled to Quebec and Newfoundland admiring rare plants that grow in these harsh environments. Dedicated to the conservation and preservation of wetlands, he was a trustee of the Bedford Land Trust and belonged to the Piscataquog Land Conservancy. A long-standing member of the New Hampshire Orchid Society, native orchids are among his plant passions, and he also has a collection of tropical orchids in his greenhouse. He has planted his 3.5-acre property in Bedford with many unusual native plants, some of which are thriving far north of their normal regions. The soil in one section has enough moisture to sustain bog-loving plants including some of his favorite insect-eating, carnivorous plants.

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Dr. George Newman of Bedford has an extensive collection of carnivorous plants including hundreds of tall pitcher plants, many of which he has grown from seed.

Along with native northern pitcher plants (Sarracenia purpurea) that have been growing outside in his bog garden for 30 years, he also has tall yellow trumpet pitchers (S. flava) and the green pitcher plant (S. oreophila) whose normal ranges are from Alabama to the North Carolina border. These southern insect-eaters happily survive outside year-round, in the bog garden next to plants native to Canada and some that grow atop Mount Washington. “It certainly is a strange mix of plants,” he says.

Predatory Plants

We are used to bugs eating our plants, but what about plants that eat bugs? All carnivorous plants grow in either extremely acidic or overly alkaline boggy soils that provide the plants with no nutrients. To survive these conditions, they have evolved ways to feed themselves by trapping insects.

Growing up in the Bronx, Newman first encountered this unique group of plants at the New York Botanical Garden when he was 10 years old, and he began collecting them soon after. Now, he has one of the largest collections of carnivorous plants in New England composed of more than 30 species and hybrids. Some of his plants are over 50 years old. He has quite a few South American pitcher plants (Heliamphora) growing in his greenhouse, but his real love is the North American pitcher plant (Sarracenia). He has collected most of the species that are native to the United States, many of them rescued from construction sites and road projects. “I have some tall yellow pitchers (S. flava) that I collected in 1974 from areas that are now gone,” he says. Pitcher plants are most often found growing in boggy meadow openings in southern pine forests. “They really are fire dependent,” he says. “Fire kills off the trees, provides fertilizer and opens the bogs to sunlight.” He only collects responsibly from the wild with the permission of landowners, and many of his plants are hybrids he has propagated himself. “It takes about 5 to 10 years to get a nice-sized plant from seed,” he explains. Newman grows most of the southern natives in containers. They are dormant in winter, spending the cold months in his basement or in a cool part of the greenhouse. When the weather warms, they are brought outside for the summer where they attract and eat a multitude of small gnats, flies and mosquitoes. “Wasps, hornets and yellow jackets are their specialty,” he says.

Tricky Trappers

Each species of carnivorous plant has developed its own methods of entrapment. Pitcher plants are considered passive, pitfall trappers. Insects are lured into the funnel-shaped pitcher by sweetly scented nectar, and as they feed, they slide further down the neck of the plant and are unable to climb back out due to downward-facing hairs. Eventually, they fall into a pool of liquid at the bottom, drown and are digested by the plant.

Sundews (Drosera) are another plant in Newman’s collection. They are considered semi-active trappers, a kind of living flypaper. They lure their prey with sweet drops of sticky glue dangling on tentacles growing along their leaf edges. Once an insect is stuck, the tentacles wrap around to smother it, and it is slowly digested. Hardy in zones 3-8, the round-leaf sundew (D. rotundifolia) is a North American native found growing wild in many states including New Hampshire.

D Dipietro

The Cape sundew was Dartmouth grad Daniel DiPietro’s introduction to carnivorous plants. He has since co-authored a book about them.

Butterworts (Pinguicula) are another sticky trapper that exude glue from tiny hairs all over their leaves, making them appear shiny, like they have been oiled or buttered. After an unlucky insect has been caught, the leaf edges will roll over to cup it while it is digested. Newman has five species of butterworts, all native to the southeast United States.

No carnivorous plant collection is complete without some Venus flytraps (Dionaea muscipula), and Newman has quite a few. They are considered active snap traps. Unlike the blood-thirsty man-eater in “Little Shop of Horrors,” these ground-hugging plants are quite small—only a few inches across with pairs of one-inch-long, hinged leaves. Sweet nectar lures in an insect where it brushes against the trigger hairs. Nothing happens after the first touch, but the trap snaps shut the second time the hairs are touched. Fine teeth along the edge of the leaves keep the victim locked in place. As the captured bug struggles, the trap closes tighter. The plant then exudes a digestive enzyme to dissolve its victim, so it can absorb its nutrients. After successfully sucking up three or four bugs, the leaves will die off and new traps will grow.

Native to a small region in North Carolina, they are considered endangered and should never be collected from the wild. “There is no reason to do that since they are easily grown from seed or tissue culture,” Newman says. The Venus flytrap is a great introduction to the captivating world of carnivorous plants. They are widely available at garden centers around the holidays. “As long as you do your homework and know what the plants need to survive, you should be successful,” he says.

From Bog to Book

When Daniel DiPietro was a student at Dartmouth College, he worked in the Life Sciences greenhouse caring for the carnivorous plant collection. It was an interest that started long before college. Like Newman, as a child he also was a frequent visitor to a botanical garden near his home which instilled an early love of plants and nature. “I didn’t start growing carnivorous plants specifically until my sophomore year of high school. I was introduced to them by my friend Alvin Liu, who had been collecting carnivorous plants since he was around seven years old. He gave me a small Cape sundew (Drosera capensis) to care for and the rest is history!” DiPietro says. Though he has added other plants to his collection, sundews are still a favorite. “I think sundews are among the most beautiful plants anywhere. I love how delicate they look and the way their dew shimmers and reflects the light,” he says. “To the untrained eye, all sundews look very similar. However, they’re actually an incredibly diverse group of plants. They come in all shapes, sizes, colors, patterns and environments, and they’re found on every continent except Antarctica.” He also finds their ability to move fascinating. “Some longer-leaved species, like Drosera regia and Drosera spiralis, can practically tie knots around captured insects over the course of a few hours,” he explains.

At first, DiPietro grew all of his carnivorous plants in tanks with artificial lighting, but now he has a huge collection of tropical carnivorous plants that he grows in his 10-by-20-foot greenhouse. “I used to have a small collection of outdoor pitcher plants, sundews and flytraps, but the winter dormancy was troublesome since my house was on the New Jersey shore and it would regularly receive very strong wind gusts. During dormancy, wind can be far more deadly than extreme cold,” he says. “After experiencing losses each season, I decided to give my remaining outdoor plants to Alvin. He has a great outdoor collection with hundreds of Sarracenia, and lots of flytraps and
sundews, too.”

DiPietro’s interest in carnivorous plants is so strong that by the time he was 20, he and his friend Liu co-authored a book about them called “Drosera of the New Jersey Pinelands, USA.”

“Alvin and I had heard about large carnivorous plant populations in Southern New Jersey, an ecological hot spot for them. The summer after we graduated high school, we went on a field trip to Colliers Mills Wildlife Management Area in Jackson Township.” They enjoyed that trip so much that they began visiting other documented sites. “Later on, we started using Google satellite maps to explore undocumented bogs and wetlands,” he says.  “At some point, we realized that we were accruing a lot of unique knowledge and habitat and ecosystem insights that nobody had thought to document, so we decided to write a book doing so.” Even though Liu is currently in medical school, they have discussed writing another book in a few years. In the meantime, both regularly post photos on Instagram under @alusplants and @plantsofdan and they have a website www.carnivorousjourney.com which is full of information.

Whether you are eight or 80, these fascinating plants are fun for all ages. To see them in the flesh, you needn’t tramp through a bog, just plan a visit to Dartmouth College in Hanover. They have about 30 species of carnivorous plants in the tropical section of the Life Sciences greenhouse. It is open to the public Tuesday, Wednesday and Friday from 11:00 a.m. to 3:00 p.m. Be sure to bring the kids. As was the case with Newman and DiPietro, it may start them on a plant-loving path.

Start Your Own Carnivorous Journey

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Glistening drops mimicking nectar entice insects onto the sundew’s sticky tentacles, which then enfold, smother and digest them.

Here are a few tips from Newman and DiPietro:

  • Know if your plants are temperate or tropical. Do your research and learn what environments your plants evolved for, then emulate them. If you do this, you can never go wrong.
  • Only use pure water—preferably distilled water, rain water or water from a reverse osmosis filter, since minerals and chemicals in tap or well water can kill the plants.
  • Provide plenty of light, either full sun or grow lights.
  • A dormant period. Most northern carnivorous plants, include Venus flytraps, need to rest in a cool place from late fall to early spring. Tropicals do not need a rest period.
  • Constant moisture but not submerged. Even during the winter dormant period, they should be kept in a shallow dish of water. Never let them dry out.
  • Proper potting mix. Newman prefers a mix of live or dried sphagnum moss, sphagnum peat and pool filter sand.
  • Remove flowers after blossoming, unless you want to keep the seeds.
  • Never feed the plants bits of raw meat! They would rather have insects.

The New England Carnivorous Plant Society hosts a show and sale every October at the New England Botanic Gardens at Tower Hill in Boylston, Massachusetts. Mark your calendars for next fall!

Categories: Gardening & Landscape