The ZZ Plant: The Aberrant Aroid

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The ZZ plant may be a fairly new introduction, but it’s already seen as a “classic houseplant.” Source: fleurenville.com

The ZZ or zeezee plant (Zamioculcas zamiifolia), also called aroid palm, has been around long enough to have become a staple houseplant for indoor decors, but that wasn’t always the case. Although discovered back in the early 19th century (it was first described botanically in 1829) in eastern Africa, its potential as a houseplant went unknown for over 150 years. Dutch horticulturists, seeing it used as an ornamental plant outdoors in tropical Asia, tried it indoors and the rest is history. By 1996, it was being mass produced. By 2000, it was essentially available all over the world.

What Is It?

The ZZ plant is an aberrant aroid.

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Most aroids look nothing like the ZeeZee plant. Source: www.fairchildgarden.org

The aroid or philodendron family is best known to most gardeners for its climbing foliage plants, including not only the ever-popular heartleaf philodendron (Philodendron hederaceum, formerly P. scandensP. cordatum and P. oxycardium), but such other indoor climbers as the pothos or devil’s ivy (Epipremnum aureum), the Swiss cheese plant (Monstera deliciosa) and the syngonium or arrowhead vine (Syngonium podophyllum). Of course, the vast family does contain a lot of other plants, including such tuberous tropicals as caladiums (Caladium hortulanum), taro (Colocasia esculentum) and any other plant commonly called an elephant’s ear, a few classic table-top houseplants peace lily (Spathiphyllum spp.) and Chinese evergreen (Aglaonema spp.) and even a few very hardy perennials for the outdoor garden, like the Jack-in-the-pulpit (Arisaema triphyllum), native to cool to cold climates in North America.

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Zamioculcas zamiifolia on the left; Zamia furfuracea, on the right. They certainly do look a lot alike, although they are not related. Source: www.plantsrescue.com & http://www.gumtree.com

However, the ZZ plant looks like no other aroid. With its clump of pinnate leaves arching outwards, you’d be more likely to mistake it for a palm or a cycad, possibly even a fern. That’s reflected in its botanical name: Zamioculcas zamiifolia. It’s named after the genus Zamia, short palmlike cycads from the New World which it certainly does resemble.

It is so aberrant that it has no truly close relatives: it is, in fact, monotypic, the only plant in the genus Zamioculcas. It even has its own subfamily that it shares with no other aroid, the Zamioculcadoideae.

A Closer Look

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Underground and out of sight are potato-shaped tuberous rhizomes. Source: Mokkie, Wikimedia Commons

Underneath the cycad-like exterior is a tuberous plant, growing from a fat, potato-like rhizome hidden or mostly hidden under the soil. Extremely thick, succulent petioles arise from the rhizome bearing about 6 to 8 pairs of very shiny, dark green leaflets. Such pinnate leaves are typical of palms, cycads and ferns, but not other aroids.

The plant usually reaches about 2 to 3 feet (60 to 90 cm) in height and spread.

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The flower of the ZZ plant is typical for an aroid. Source:  Mokkie, Wikimedia Commons

Small, typically aroid inflorescences, with a greenish to bronze spathe (leaf-like bract) from which emerges a cream to brown colored spadix (flower spike), appear on very short stems at the base of the plant, often so well hidden you don’t even notice them. Certainly, they contribute little to the plant’s appearance.

One Tough Cookie

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You can put a ZZ plant almost anywhere indoors, even a dark corner, and it will survive for many, many months. Source: Eveline Mallmann, pinterest.ca

The ZZ plant is extremely tolerant of indoor conditions (it also makes an easy-to-grow shade plant for the tropics, but that’s another story). It will grow just about anywhere, from full sun to deep shade, and seems to thrive in neglect. Even so, you’ll get better results if you “treat it kindly,” and that would include giving it good light with some direct sun each day and avoiding spots in full sun during the hotter months of the year.

Of course, while it will “hold” for months in a dark corner that receives no sunlight at all, that will eventually kill it: it’s a living plant after all and all green plants need at least some light!

Rumor has it that the ZZ plant never needs to be watered. That’s nonsense, of course: all living plants need water!

This plant is essentially a succulent (again, aberrant in aroids), native to forests and savannahs where severe drought can occur. As a result, it prefers fairly arid conditions to the humid jungle-like environment most other aroids favor. That helps make it easy to grow, as it will tolerate considerable neglect. Even so, it does best when watered regularly, as soon as the soil is dry to the touch. And when you do water, do so thoroughly, completely humidifying the root ball.

Overwatering can lead to rot, so be sure the growing mix is almost dry before watering again. Sink your index in the substrate to the second joint: if it’s still moist, it’s not yet time to water!

It will tolerate so much neglect you can actually not water it at all for months on end. That will eventually push it into dormancy, though, a state from which it will (slowly) recover when you start watering again. I had a friend whose ZZ plant accidentally got stored in a box for over 2 years: therefore, with no light or water. It was leafless by then, of course, but when water was applied again, it started to regrow, albeit several months later.

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The ZZ plant will grow in almost any decor… but it doesn’t like cold temperatures. Source: www.bakker.com

This plant’s well-deserved “tough-as-nails” reputation only applies if you keep it fairly warm. It is perfectly happy at normal indoor temperatures, that is, between 65° and 80 °F (18 °C and 26 °C), but does not like cool temperatures and can die if exposed to temperatures below 60 °F (15 °C) for any extended period. If you put yours outside for the summer, do make sure you bring it back inside early.

The ZZ plant is certainly not a heavy feeder and will probably do fine even if you never fertilize it, but to maintain good growth, a regular fertilizer regime at ⅛ to ¼ of the recommended rate, applied during its spring through early fall growing season, is best. You can use the fertilizer of your choice.

Finally, repot after a few years or when the plant outgrows its pot.

Propagation

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A ZZ plant cut into two and ready to be planted. Source: www.jackwallington.com

Mature plants can be divided, although they may take 5 years or more to reach a size where you’d be comfortable trying. Study at your plant and if you can see it’s composed of two or three distinct clumps, you can unpot it, separate the clumps by cutting between them with a sharp knife and repot them individually.

Mostly, though, home gardeners start new plants from leaflet cuttings.

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Leaf cuttings at various stages. Source: edis.ifas.ufl.edu

The leaflets are actually quite fragile and easily knocked off: always a good excuse to try a bit of multiplication. Just insert the lower end of the leaflet into a moist growing medium and water as needed so it doesn’t become totally dry … and that means not very often. Perhaps once a month or so.

An underground tuber-like growth forms first and, then roots and finally, a first leaf. Sometimes the green leaflet has time to turn yellow, then brown before there is any visible sign of life above ground, but don’t give up: there is probably a tuber at the base of the leaf and, if so, a new plant will form, although that can take a year, sometimes even two … and no, that is not an exaggeration!

You can also use an entire leaf as a cutting, but you’ll still just get one plant at the end.

Pests and Problems

As mentioned, rot is the most likely cause of any ZZ plant death. It usually sets in when the plant is left soaking in water for long periods. Remember, with this plant, water only when the potting mix is truly dry to the touch.

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Scale insects and their sticky dejections on a ZZ plant. Source: ask.extension.org

Mealybugs and scale insects just love the ZZ plant and are hard to control. I once tried putting a scale-infested plant into complete dormancy, forcing it to lose all its leaves. Then I dug up and thoroughly cleaned the rhizomes. When it grew back many months later, the scale insects came back too!

Try removing any visible insects with a soft, soapy cloth, then spray repeatedly with isopropyl alcohol (rubbing alcohol) to, hopefully, kill any nymphs. If that doesn’t work, toss the plant and only use the pot again after a truly thorough cleaning.

Toxic or Not?

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The ZZ plant is not edible, but then, apparently not as poisonous as once thought either. Source: clipartxtras.com

The ZZ plant is an aroid, all of which are usually considered poisonous because they produce calcium oxalate, which can cause painful irritations if ingested. For years, the ZZ plant was thus deemed “guilty by association” and even listed by many sources as highly toxic.

However, recent studies suggest that the ZZ plant is considerably less toxic than most other aroids and in fact, possibly not toxic at all.

While waiting for further studies to be done, it would still be wise to keep this plant out of reach of children and pets.

Cultivars

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Variegated ZZ plant. Source: MonsteraCo.

Recently, a few cultivars have appeared, none widely available at the moment.

‘Raven’, with dark purple black foliage on a more compact plant (30 inches/75 cm).

‘Zamicro’, a dwarf version (16 inches x 12 inches/40 cm x 30 cm) for tight spots.

There is also a variegated ZZ plant out there (I saw one specimen in the Berlin Botanical Garden and it was gorgeous!), but it’s outrageously expensive.


The ZZ plant: original and easy to the point of being nearly unkillable. Give one soon as a gift to some poor brown thumber who desperately needs a bit of a confidence boost in his or her gardening abilities!

A South Florida Garden Tour

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Day Two: Taking in the Show at TPIE

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A small section of the show at TPIE.

The TPIE (Tropical Plant Industry Exhibition) is the most important foliage and tropical plant show in North America. It’s held every January in Fort Lauderdale, Florida, this year from January 18 to 20. I was able to attend this year as part of the 3-day media tour organized by the FNGLA (Florida Nursery, Growers and Landscapers Association) for members of the Garden Writers Association.

TPIE is a trade show showcasing the latest trends in foliage, floral and tropical plants. It covers nearly 5 acres (2 hectares), a virtual indoor garden of show-stopping display and gorgeous plants. It’s essentially designed to allow nurseries, and especially garden centers from eastern North America, to meet up with suppliers of products and plants from all over the world. There were some 400 booths at this year’s show including suppliers from over 30 different countries.

It’s not the first time I’ve attended this show. I’ve been twice before and indeed I’d go every year if I could. It is by far my favorite trade show… and as a garden writer who has to keep up-to-date on the latest garden trends and plants, I visit quite a few over the course of a typical year.

For me, it’s a chance to peruse the newest, most intriguing and most attractive houseplants, plus also the latest in pots and products: things I’ll be able to write about in this blog. There are no plant sales: everything is strictly wholesale… but at least I can start making a list of new plants I want to try.

Visiting the show takes essentially all day. Our group started with a very interesting lecture on how lifestyle trends affect how people buy and use plants followed by a guided tour of the showroom. Then we were on our own, schmoozing with all the nursery people. I took a ton of pictures!

Latest Trends

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Cooking and edible plants ought to go together, right? Here, containers of herbs and vegetables are incorporated directly into the kitchen counter. Genial!

Wear Your Plants

This year it seems that gardeners will not only be growing plants, they’ll also be wearing them. Here are a few examples.

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A tillandsia lapel pin or brooch.

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Here comes the bride, all dressed in succulents!

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Even I’ve caught the bug and am wearing a tillandsia necklace. Photo: Jo Ellen Myers Sharp

Outstanding Displays

I could have presented 50 pictures here, but I cut it down to a few favorites.

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A wall of color-coordinated vandas certainly draws the eye at Silver Vase Orchids & Bromeliads.

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My thought is you really can’t have too many colors in a show display.

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I liked the “welcome to my house” look of this display

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A mind-boggling choice of orchids.

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The display by Bullis Bromeliads won first prize in its category.

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This huge display, by Plants in the City, was spectacular, showing a city street with the Brooklyn bridge in the background. I can only show part of it: it was always too crowded for me to take pictures.

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The display by Excelsa Gardens was an award-winner for its class.

Plants Worth Noting

Just a few of the superb plants I noted. Some of the will be making it to a garden center near you this spring!

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Exacum ‘Kandy’ has enormous flowers compared to the original Exacum affine, a some-what forgotten houseplant with paler flowers once sold under the name Persian violet.

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The Soiree series of Madagascar perwinkle (Catharanthus roseus) produces masses of much tinier flowers than any I have even seen.

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There were so many bromeliads, it was hard to choose a favorite, but I finally did: Neoregelia ‘Sunkiss’

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I’ve been seeing this Sansevieria ‘Fernwood’, with its very thin almost wispy leaves, in garden centers, but this is the first time I’ve seen it labelled.

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A dwarf zee zee plant: how cool is that? Zamioculcas zamiifolia ‘Zamicro’.

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This was my favorite foliage plant for color: Aglaonema ‘Sparkling Sarah’.

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Tillandsia ‘Samantha’: definitely a Best in Show in my eyes!

Julia Hofley, houseplant expert and fellow garden writer, and I checked notes and we both decided this plant, Tillandsia ‘Samantha’, was our favorite new plant. Well, guess what? So did the judges! It was accorded not just one, but two awards: Attendee’s Choice award and Most Unusual Plant.

Colorful Containers

This show offers lots of truly attractive containers… but using some of them is going to making gardening more difficult, as they rarely seem to have drainage holes. You might want to get out a drill if you buy one. Here are few of the more interesting ones.

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Very cute pots for a mini garden… I’m not sure how the plants will get enough light, though!

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Pineapple-shaped pots with a Tillandsia topping.

Lessons Learned

TPIE is a good place to go to learn how plants are treated in nurseries. Here are a few examples.

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Some plants (here Fittonia) are shipped simply as stem cuttings dropped into a plastic bag: who would have thought it was so easy!

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All those twisted, spiralled and braided Sansevieria cylindrica plants you see in stores are actually just leaf cuttings. Here is what they look like, freshly imported from Asia and dusted with a fungicide, before they are potted up.

Horrorculture

I’m sorry, but there are some horticultural practices I don’t approve of, notably when gardeners are being lead to buy by a product that is not what it is purported to be. I call that horrorculture rather than horticulture.

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Haworthias covered in paint: if you did this to puppies or chicks, you’d be arrested! It just makes me sick to see it!

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Cactus spray-painted to make them more saleable. Atrocious.

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These mosses aren’t mosses at all: they’re coloured dried reindeer moss (Cladonia rangiferina) and quite dead. As long as you know they aren’t mosses, that’s fine. But beginning gardeners often ask me how often to water them, a sign that information is not getting out.

Just Weird

I’m not complaining: I like weird.

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A moss-filled flamingo topiary filled with pink polka dot plants (Hypoestes phyllostachya).

The Party’s Over!

There was a Happy Hour for all the exhibitors and guests after the show… but I was so burned out I returned to my hotel… to work on preparing this blog.

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