growing carnivorous plants, with peter d’amato

A WOODEN WINDOW BOX lined with plastic and filled with sundews and pitcher plants will attract more attention than one full of geraniums, writes Peter D’Amato in “The Savage Garden,” the fascinating bible of carnivorous plants that’s just out in an updated 15^th-anniversary edition. Ready to try a mini-bog in a pot or the ground, or a hanging basket of tropical pitcher plants in your house–and also perhaps win a copy of the book?

prefer the podcast?

GROWING CARNIVOROUS PLANTS was the subject of the latest edition of my weekly public radio show and podcast, with Peter D’Amato of California Carnivores, author of “The Savage Garden” (Amazon affiliate link) as my guest. Listen anywhere, anytime: Locally, in my Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) region, “A Way to Garden” airs on Robin Hood Radio’s three stations on Monday at 8:30 AM Eastern, with a rerun at 8:30 Saturdays. It is available free on iTunes, the Stitcher app, or streaming from RobinHoodRadio.com or via its RSS feed. The July 15, 2013 show can be streamed here now. Robin Hood is the smallest NPR station in the nation; our garden show marked the start of its fourth year in March, and is syndicated via PRX.

The backstory: About 20 years ago my longtime friend and fellow garden writer Ken Druse and I were working on a book about native plants, called “The Natural Habitat Garden,” and I joined Ken as he traveled around the country photographing natives, in nature and in gardens.

One of our wildest stops was up in Sebastopol, California, at California Carnivores, which has been open and dedicated to cultivating these dramatics plants–including various native American species–since 1989.  (A highly recommended destination if you are near San Francisco.) In 1998, Peter wrote “The Savage Garden,” but a lot has changed in carnivores in 15 years since the first edition–and even more so in the 40 years D’Amato has been growing them.

So many new species have been discovered in places such as the Philippines. “We’re now at an estimated 800 to 1,000 species of carnivorous plants worldwide,” says Peter; for many years the number was thought to be about 600. At the time of the first edition, for instance, there were 80 known species of Nepenthes (below N. rafflesiana); those outlandish-looking “tropical pitchers” are now counted at about 150 species.

Speaking of which: In the “houseplant section” greenhouse of my local garden center, I’ve been admiring the giant hanging baskets of Nepenthes. Can I really bring one home and make it happy in my house? Apparently yes, Peter says—noting that two Nepenthes varieties (one called ‘Miranda,’ and another that’s a hybrid of N. alata) are being propagated vegetatively in recent years, and sold widely from Paris to London to the U.S. to Hong Kong.

Nepenthes do require “rather exacting conditions,” though, he explains:

• They do well at room temperature–and can take temperatures down into 50s and 60s  and up to the 70s and 80s.
• Like all carnivorous plants, they need sun: extremely bright or sunny window exposure, such as a sun room, or in your brightest window, for instance.
• They need to be watered daily, but not with hard water that’s full of minerals. Use water that’s purified by reverse osmosis, or use rainwater or distilled water. (DIY countertop or faucet filters such as those that inside special water pitchers are not sufficient to lower the minerals.)
• Avoid putting fertilizer into the potting medium of any carnivorous plants. Again, they don’t like high mineral content, but you can make a diluted solution of the fertilizer, and spray or otherwise wet down the foliage perhaps twice a month.  (The fertilizer they use at California Carnivores.)
• More on Nepenthes, at the nursery website.

did you know? carnivorous-plant ‘aha’s’

• All carnivorous plants are flowering plants. The “pitchers,” though highly ornamental, are not blooms but modified leaves—“forming traps to lure, drug, catch, kill and digest insects,” says Peter.
• They adapted to get nutrition this way so they can survive in the natural habitats they hail from—such as wet grassy savannahs in the Southeast, or bogs in New England, or mountain forests of Southeast Asia. Other plants would struggle in such areas, where usually the soil is peaty or sandy, with water trickling through it and even high rainfall–water that leaches out excess minerals. “Carnivorous plants have adapted to catch all these vitamin pills with legs and wings that we call insects,” says Peter.
• The United States has more carnivorous plant genera than anywhere else on the planet. (Particularly the Southeast, from Southern New Jersey to Northern Florida and the Gulf Coast, but there are West Coast species as well.)  The Southeast used to be an amazing belt of habitat for carnivores—but many are now on the verge of extinction, says Peter. “Only 5 percent of our native carnivorous plant habitats remain in the Southeast,” he says.
• American pitcher plants have to be about 5-8 years old from seed to reach flowering age. When they finally do so, the flowers are timed to open before the year’s new pitchers develop, because the plants don’t want to catch their pollinators in the pitchers!

making a mini-bog

ALL CARNIVOROUS PLANTS must be container plants—unless you live in a bog, says Peter. That said, the “container” can be an actual vessel (like to old washtub above, or a whiskey barrel), or a sort of simulated mini-bog set into the ground, using a rubber or plastic liner or a pot, for instance, and filled with a proper growing medium. But these plants cannot live in garden soil.

Most plants in a simulated mini-bog are simply potted ones that sit in bowls of purified water so they’re always wet, year round, even when dormant and the water freezes.

Which kind of pot to choose? An undrained container 12 inches across or larger is fine, Peter says (or a shallow depression in the ground, about a foot deep, lined with a pond liner). If it’s smallish, it will require regular watering–even daily–so choose accordingly.

Alternatively, you can use a mini-bog container that has drainage holes, and would sit in a much larger water bowl—and that’s often much easier, Peter says. The bigger reservoir will provide moisture over a longer time than a small dish garden (above, a pitcher plant in a small dish).

If you’re growing in a pot with drainage, use sphagnum moss to cover the hole (to keep the growing medium in the pot). Mix your growing medium of 20 percent washed sand (either horticultural or play sand for sandboxes), or 20 percent Perlite, to either of which you add 80 percent sphagnum moss. Make sure the sphagnum is pure, with no fertilizer added, “which has become a big problem the last few years,” says Peter, as more potting mediums come already fertilized.

Premix your dry ingredients with a lot of water—again, not mineral-rich water!—until “it’s like soft mud,” he says.

Plants come two ways: potted, or bare root. Bare root are easier to handle in late winter, during dormancy, than during active growth, to minimize transplant shock. Potted plants are even easier and more flexible, because the medium around the roots needn’t be disturbed in the process of transplanting–and pots can even just be plunged in the medium in your larger garden container.

Many bog plants can take some winter, including freezes, but in extreme Northern zones they can be given winter shelter in a bright, cold location, such as an unheated or barely heated porch. Darkness during dormancy invites rotting; keep that in mind when selecting a spot.

More on growing carnivores on Peter’s website, or for the complete how-to, “The Savage Garden” is your best companion.

how to win ‘the savage garden’

I’VE PURCHASED TWO EXTRA COPIES of “The Savage Garden” (Amazon affiliate link) to share with you. To enter, all you have to do is comment below, answering this question:

Have you ever grown a carnivorous plant? Have you ever seen them in nature, or in a botanical garden display, perhaps?

I’ve seen them in the wild and in gardens (and at California Carnivores–a great tourist stop in Sonoma County wine country) but never grown them myself. Re-reading “The Savage Garden,” I feel inspired to  to try a mini-bog, at least a dish garden-sized one–and to finally buy that crazy-looking Nepenthes hanging basket at my garden center.

Don’t worry if you’re shy or have no answer to the question–just say “count me in” or something like that, and I will. Two winners will be drawn at random after entries close at midnight on Monday, July 22. U.S. and Canada only. Winners will be notified by email. Good luck to all.

(Photos reprinted with permission from “The Savage Garden, Revised: Cultivating Carnivorous Plants,” by Peter D’Amato; Ten Speed Press, © 2013. Top photo of Drosera with beetle and photo of Sarracenia minor ‘Okee Giant’ by Jonathan Chester/Extreme Images, Inc. Nepenthes photo by Sharon Bergeron. Mini-bog in an antique tub by Jana Olson Drobinsky.)