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| Sundew (Drosera) |
Growing
Carnivorous Plants
by Bryan Fischer, Horticulturist, Gardens on Spring Creek
Last winter, I made the
ill-fated mistake of dropping a large Mangave on my carnivorous plant collection.
The event was crushing in more ways than one. In homage to the collection that
was, I wanted to share regarding my experience growing these quirky plants.
Not just the ubiquitous Venus
fly trap, carnivorous plants encompass a diverse and fascinating group of
plants originating from areas with very poor soil or water concentrations of
essential nutrients. While they still photosynthesize to produce their energy
(carbs, like other plants, because even plants can’t leave carbs alone), they
use insects to supplement the limited nutrient spread provided by the
relatively nutrient-poor soils or water in which they grow.
I had long ago given up on
cultivating carnivorous plants after killing my fair share of Venus fly traps
and pitcher plants, among the most common carnivorous plants in stores. What I
later found out made me reconsider: Venus fly traps and many pitcher plants
require annual chilling periods to maintain vigor throughout their lives. Such
plants will fail to thrive unless they spend several months at a temperature colder
than that which can be provided in the average house, which is a major
contributing factor to the mysterious, slow decline many who have tried to grow
carnivorous plants have witnessed.
Many carnivorous plants,
however, like the tropical sundews (Drosera), bladderworts (Utriculatira),
and butterworts (Pinguicula) either don’t require dormancy periods at
all or have dormancy needs that can be met simply by adjusting watering
frequency, making them much more well suited to life as houseplants. What’s
more: these plants can easily be purchased online and shipped to your door for
surprisingly reasonable prices.
Hundreds of species of
carnivorous plants exist across the globe, representing several different
independent evolution events. As a result, a surprising diversity of mechanics
are employed by plants to consume insects, much to the delight of plant nerds near
and far! These plants can be found in a number of habitats, ranging from bogs
just 70 miles from Fort Collins (in the case of Drosera rotundifolia) on
the edge of North Park, where winter temperatures regularly fall to -20 degrees
Fahrenheit to xeric mountainsides in Mexico, where some carnivorous plants act
as succulents, intermittently abandoning carnivory for a succulent growth habit
and ceasing growth as cold temperatures or dry conditions dictate.
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| Bladderwort (Pinguicula sp.) with captured prey |
We are all aware of the Venus
fly trap, native to bogs in the Southeastern United States, but some
lesser-known plants use sticky, flypaper-like leaves (Pinguicula spp.);
others use tubes filled with digestive fluids (think verdant pit of fly-doom),
and another pair of groups uses leaves covered in enzyme-laden hairs (the
sundews, including Drosera spp. and dewey pines, the Drosophyllum
sp.). Some, like bladderworts (Utriculaira
spp.) even have underground (or underwater) traps that snap shut in the
blink of an eye, lassoing or enveloping quick moving prey. The best part? You
can grow many of these easily indoors if you meet their water and potting mix
requirements.
Among the easiest for home
culture, many Drosera species make ideal starter carnivorous plants. If
potted in a media of half peat and half perlite, they will grow with relative
ease in dappled light indoors. Many of these sundews, like cape sundew from
South Africa (D. capensis), don’t require any major change in culture
through the year, either.
Most Drosera grow steadily with consistent moisture, light, and temperature. These plants can be easily purchased online and are available with a range of leaf shapes, colors and sizes ranging from cute, round and green to almost alien looking, tentacle-like, red leaves. Their leaves are covered in colored hairs, each with a glistening bead of baited, enzymatic juice at its end, ready for an unsuspecting fruit fly or fungus gnat—talk about a two for one! Think of them as pest management and some solid botanical novelty all wrapped into a single package.
Another favorite carnivorous
plant of mine for home culture, Utricularia sandersonii exceeded all my
expectations when I began growing it over a year ago. Despite its horrid common
name (Sanderson’s bladderwort), the plant is downright adorable, creating a mat
of tiny, chartreuse leaves followed by liberal production of flowers that look more
like pairs of lavender colored bunny ears bobbing atop threadlike stems. Mine
grew almost effortlessly in the living sphagnum moss that it came shipped with
just in the bottom of a small glass vase. All it required of me was a sunny
windowsill and regular watering.
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Perhaps strangest to me, butterworts (Pinguicula) have adapted to survive not only drought but periods of cold by intermittently abandoning carnivory in favor of growing as succulents, which frankly, seems like a recipe that could make them the crown jewel of millennial houseplant ownership. If a dry period can be provided during the winter months (just water them like your succulents), many of these attractive tropical carnivores can make attractive windowsill ornaments. More prone to rot than other carnivorous plants, they should be grown in a lighter media of two parts perlite and one part peat moss. They bloom as well, producing violet-like purple, red, pink or white flowers on tall, wiry stalks. When actively supplementing their diet with their usual pea-brained fare, their broad, flat leaves lure invertebrates with an attractant before trapping them with a sort of fly paper-like adhesive that coats leaf surfaces.
Whatever carnivorous plant you
may choose to grow, be sure to use very pure water for your waterings. Growing
in such places as bogs and mountainsides, most carnivores have very low
tolerance for dissolved nutrients and salts in their water supply. Regular
waterings with tap water in most parts of the country can reduce vigor or kill
these plants over time. While fine to use in a pinch here and there, most
waterings should be done with either rainwater / snowmelt, or filtered water (the
goal is to reduce dissolved solid content when shopping for a filter). Store-bought distilled or de-ionoized water can
also be used. While probably the most demanding aspect of growing these plants,
I haven’t found it to be too burdensome.
So, if you’re finding yourself
intrigued, consider investing in a South African Drosera or tropical
bladderwort, which are likely the two plants discussed here that are simplest
plants to grow. Be sure to make your own potting mix, as mentioned above, and only
use pure water to keep the plant hydrated.