University of Vermont
Department of Plant and Soil Science

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EASY HOUSEPLANTS—ZZ PLANT

Dr. Leonard Perry, Horticulture Professor Emeritus
University of Vermont

ZZ plant is an easy-care and popular houseplant, one which has become widely available in recent years.  Since it tolerates a range of conditions, you often find it in commercial use such as restaurants and offices. 

The odd common name is just the letters from the scientific name, which is a mouthful (Zamioculcas zamiifolia).  Also, it may be found under the names Zanzibar Gem or emerald palm, the first name relating to its origins in eastern Africa, the second name referring to its bright and shiny, emerald green leaves.  The species name refers to the fact that it resembles a cycad genus (Zamia).

It is in the Arum or Araceae family, related to the dumbcane, Chinese evergreen, peace lily and philodendron.  As with these other members of this family, ZZ plant contains calcium oxalate crystals in its sap which, when ingested, cause severe irritation and burning.  So, keep this plant away from pets and children that may chew leaves. You may see other mentions of this plant being highly toxic, claims which are overblown and have not been proven.

Similar to other “clean air” houseplants which have been shown in studies since the 1980’s to remove volatile pollutants from indoor air, so does the ZZ plant.  Such pollutants come, for instance, from manufactured furniture, finishes, carpets, chlorinated water, and power equipment stored in garages or attached buildings to homes. In a study at the University of Copenhagen in 2014, ZZ plant was found to remove pollutants such as benzene, toluene, ethylbenzene, and zylene from the air. 

Although this plant was first described in a publication in 1829, it wasn’t until the mid-1990’s that it became more known and seen for sale, due to extensive propagation by Dutch nurseries in South Africa and their worldwide distribution of this plant.  It is most easily propagated by dividing the roots (rhizomes) with young stems attached.  Leaf cuttings, placed in a pot covered with a plastic bag to maintain humidity, may take a year to root.

The ZZ plant grows similar to a palm (another name is aroid palm), with stems from the plant base where they are thickened.  “Stems” are actually the leaves, along which the six to eight pairs of leaflets are neatly arranged.  While most stems grow upright, ones that arch over and flop may be unattractive and cut off.  Under ideal conditions, plants may reach two to three feet high and wide.  Plants survive fine without fertilizer, but will grow more if a general-purpose houseplant fertilizer is applied when new growth emerges. 

Leaflets are a couple inches long and an inch or so wide indoors, but may be double that outdoors. They’re somewhat thick, stiff, and with a waxy sheen may be mistaken as being plastic.  If the pointed leaflet tips turn brow, the air may be too dry.  This can be remedied by placing plants on a try of pebbles, kept moist, or using a room humidifier nearby.

If leaves turn yellow and fall off, this is usually a sign that plants are too wet—they’d rather be too dry than too wet—or under severe drought.  If the soil gets too dry, just water and plants recover.  Plants can survive a month or two without water. They have thick rhizomes for roots, which look a bit like potatoes, that enable them to store water for long periods.

If leaves curl and have scald marks, they’re getting too much light.  This plant prefers bright, but indirect light, yet can tolerate low light conditions.  It will survive indoors, away from windows, with just artificial light.  Along with the cast iron plant (Aspidistra) and bow string hemp (Sansevieria), ZZ plant is one of the best choices for low light.

The spathe-type flowers, followed by white berries, are really not seen indoors but only when grown outdoors.  It is only seen outdoors in quite warm climates (USDA zones 9 and warmer), not tolerating temperatures much below 45 degrees (F).  Indoors, it grows fine between 60 and 80 degrees.  

Plants survive when pot-bound, and may grow more slowly.  If you do need to repot, use a well-draining houseplant potting mix, not garden soil.  Don’t use too large a pot, as the soil may stay too wet.  A clay pot will keep the soil drier than a plastic one, which is what this plant needs.  Also, a clay or ceramic pot (make sure it has drainage holes in the bottom) is heavier and will help keep this plant from tipping over, as it may get top-heavy.

ZZ plant really gets no pests or diseases, except for root rot from staying too wet, and perhaps brown scale insects on leaves.  The latter can be removed easily with rubbing alcohol and a cotton swab.  If leaves get dusty, just wipe them off with a damp cloth.  Leaf shine products are not recommended nor even needed, as leaves naturally are quite shiny. 

If you haven’t seen ZZ plant, watch for it in offices and stores.  It is available for sale in many greenhouses and even plant departments of chain stores.  If you’re new to houseplants, or think you have a brown thumb, this plant is a good choice.  If you buy one, just remember that the key to care is virtually no care.

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