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.
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