Plant of the Month: January 2012
by Arthur Lee
Jacobson from his website www.arthurleej.com
Chaya. Mayan
Tree-Spinach, Cabbage Star
Cnidoscolus
aconitifolius
(Mill.) I.M. Johnst. 1923 ssp. aconitifolius
= Cnidoscolus
Chayamansa McVaugh 1944
= Jatropha aconitifolia
L. var. inermis
Calvino 1919
Euphorbiaceæ:
Spurge Family
The Chaya plant offers extraordinary
attributes as a food crop: potential year-round yields; highly
nutritious; tasty; productive; minimal pest or disease susceptibility;
tolerant of diverse growing conditions; easily propagated; perennial;
handsome foliage; fragrant flowers that attract butterflies, moths and
bees; useful forage for domestic animals.
On the minus side . . . it is
freeze-tender; its leaves should be cooked rather than ingested raw; it
has but few cultivars, and their relative merit and behavior are
practically undocumented. Overall, more people should know about, and
grow, Chaya --hence this article.
My Chaya plant
the day I received it
August 2010 
The book Edible Leaves
of the Tropics was my introduction to Chaya. Inasmuch as I
am in the midst of a multi-year study of edible houseplants, this book
has proved most useful. Though no houseplant guidebooks known to me
suggest Chaya, nonetheless it was worth testing indoors. After all,
some of its cousins have been tried sparingly as houseplants, such as
Jatropha
Podagraia (Gout Plant. Nettle Spurge. Tartogo. Australian
Bottle-plant. Buddha Belly Plant. Guatemala Rhubarb), and Manihot
esculenta (Bitter Cassava. Manioc. Tapioca. Sweet-potato
Tree.
Brazilian Arrowroot. In Spanish: Yuca).
Moreover, various people have reported on the internet that they have
treated Chaya as a container plant: inside during winter, outside
during summer. For example, Neem
Tree Farms on its website reports of
Chaya: "In colder climates they grow well in a sunny window, although
you'll want to put them outside once temperatures are consistently
above freezing. They've consistently come back from the ground with
temperatures as low as the mid-20s, but they're among the first plants
to lose their leaves when it gets near 30 degrees." Therefore, I bought
a mail order Chaya plant in August 2010. It flew from Florida to
Seattle in an airplane.
In the preface to the 3rd (1998) edition
of the aforementioned book, Dr. Franklin W.
Martin ranks Chaya as one of the top 5 perennial tropical leaf crops:
"of the thousands of leafy vegetables available throughout the tropics,
relatively few are great winners, and these should be emphasized
first." (p. ix) "Chaya is an extremely promising species for its high
nutritional value, exceptional drought tolerance, and productivity even
in very poor growing conditions. An attractive perennial shrub, it
produces abundant quantities of large, dark green leaves. Chaya thrives
on a wide range of soils in both hot, rainy climates and areas with
occasional drought. It prefers good drainage, but can survive some
waterlogging. Leaves are larger and more tender when grown in partial
shade." (p. 30).
My Chaya experience has been positive.
It grew indoors during the cold months of Seattle, and was brought
outside by July. The shock of changing from the subdued inside light to
the direct sunshine outside, sunburned its leaves --but the plant grew
a new set. Then I brought it back inside. I easily rooted a cutting
from it. There were a few spider mites at one time, but they have been
long gone. I fertilize mine with Safer brand Oxygen Plus liquid "plant
food" --mainly a nitrogen fertilizer. I keep the plant warm when
indoors, ideally between 67 degrees F at night and about 10 degrees
warmer during the day. Supplied with ample water, it makes non-stop
growth. If it were in a cooler, drier, part of the house, it certainly
would grow less.
Chaya leaves are used as one would
cooked spinach or chard; they can be used to wrap tamales, and have
been juiced. In the kitchen, I use Chaya leaves in boiled dishes,
frying, and as pizza toppings. Cooking is vital: "Uncooked Chaya leaves
contain a cyanogenic glycoside [linamarin] that produce hydrogen
cyanide upon tissue damage. The cooking time required to lower HCN to
safe levels is about 15 minutes." [Plant
Resources of Tropical Africa:
Vol. 2, Vegetables (2004); p. 200]
Chaya female flowers
Other reports, and my own
experience, have demonstrated that one need not boil for so long; 3 or
4 minutes seem to suffice. But the safe time required will depend on
the clone cooked; the quantity; and even the cookware. It is widely
reported that people ought not cook Chaya in aluminum, because a toxic
chemical reaction can cause diarrhea. I have tested this, and my
clone's un-chopped leaves, boiled 4 minutes in an aluminum pot, have
not bothered me. Still, you should figure "better safe, than sorry"
--so avoid aluminum. If that is not enough, a 2006 ECHO Plant
Information Sheet cautions: "Avoid breathing the vapors produced during
cooking Chaya."
However, at least 4 Chaya cultivars /
clones have been named (described below); each with unique cyanogenic
glycoside levels, as well as nutrition, yield, and --perhaps-- cassava
common mosaic virus prevalence. I hope someone grows all 4
cultivars in
one garden, observes and tests them. Ideally, virus-free plants would
be compared to virus-containing plants. A possible place for this to
occur is the Educational Concerns For Hunger Organization (ECHO) of
Fort Myers, Florida. ECHO published several articles on Chaya
(available from its website) and helpfully sends all over the
developing world cuttings of Chaya and other edible tropical plants.
The botanical history of Chaya is as
follows. In the 1700s originally classified in genus Jatropha, Chaya
and its relatives were transferred to genus Cnidoscolus in
1827, by
Johann Baptist Emanuel Pohl (1782 - 1834). The unwieldy name
Cnidoscolus
was derived from the Greek knide
(nettle), and skolos
(thorn, prickle or sting). The initial c is silent, so pronunciation is
ni-dos-kol-us, with the accent on either the second or third syllable.
Cnidoscolus
is more closely related to
Manihot
than to Jatropha.
Estimates of the number of Cnidoscolus
species vary from 50 to 93. All are herbs, shrubs or trees from the New
World, specifically the southern U.S. (only 4 species of dry sandy
woods; with common names such as Tread-softly, Spurge Nettle and Bull
Nettle) into South America. In the 2001 book Food Plants
of the Sonoran
Desert by Wendy C. Hodgson: of Cnidoscolus
species, 9 are known to have
edible leaves, protein- and oil-rich seeds, and potato-like roots (p.
160). Some species are used medicinally. One, Cnidoscolus elasticus
Lundell of northen Mexico, is a source of rubber, its latex containing
44 - 50% rubber.
My Chaya plant in a pot with croton cultivars
August 2011
Most Cnidoscolus species
are protected
by horribly stinging hairs, more painful to human skin than common
nettles (Urtica
species). In the wild, the ancestor of the domesticated
Chaya grows from extreme S Texas to Colombia; from sea level to 4,265
feet (1,300m) elevation in moist and dry thickets in open forests. It
can survive high temperatures, deep shade, periodic inundations or
droughts. But it stings people.
In 1944, botanist Rogers McVaugh (1909
- 2009) separated the cultivated from the wild species; Chaya mansa is
domesticated and sting-free, while Chaya
brava is the wild stinging
form; Chayamansa
is a hybrid word of the Mayan chay and the Latin mansa
meaning house, dwelling or farm. McVaugh's specific name Chayamansa
refers to the domesticated Chaya only. But in recent years, taxonomists
prefer to use the designation Cnidoscolus
aconitifolius Chayamansa
Group to refer to the stingless (or practically so), cultivated Chaya
plants. Calling them a separate species (Cnidoscolus Chayamansa)
from
Cnidoscolus
aconitifolius is unwarranted.
Sometime in the pre-Columbian period,
Chaya's cultivated, non-stinging versions are believed to have
originated by the Maya in SE Mexico's dry tropics in the Yucatán
Peninsula, and were exported to nearby Belize and Guatemala. Chaya was
introduced to Cuba, and thence by Dr. Mario Calvino to Florida in 1918
(USDA Department of Plant Introduction accession No. 46862). The famous
plant explorer David Fairchild wrote in 1947: "a favorite vegetable
with us in early summer. Its tender shoots make spinach seem
uninteresting, and fritters made from them can't be beat."
My Chaya plant indoors
January 2012
Curiously, in Mexico the consensus is
that the stinging Chaya plants taste better than the stingless
cultivars. Jim Conrad's Naturalist newsletter August
1st 2010, supplies
an overview: "In most of Mexico this is called Mala Mujer (mu-HER),
which translates to bad woman, because the plant abundantly bears long,
sharp hairs that produce burning, nettle-like stings. There's a
cultivated form of Mala Mujer known as Chaya. Chaya is one of the
Maya's most important plants, for it bears few or no stinging hairs,
and its leaves are good to eat, very tasty and unbelievably nutritious.
Chaya is richer in iron than spinach, and is very rich in potassium and
calcium. Chaya's leaves are much less deeply lobed than those of Mala
Mujer, and the whole Chaya plant is less gangly looking than Mala Mujer
--more leafy and compact."
Regarding the nutritional content of
Chaya leaves, every source agrees that they are rich. It should be
obvious that the richness will vary from clone to clone, and vary
according to growing conditions. Using search engines, I located
several different published analyses. Here is a brief and very partial
overview: Protein content reports range from 2.71 - 8.25 per cent.
Calcium content reports range from 140 - 500 mg. per 100 g. Iron
content reports range from 2 - 14.04 mg. per 100 g. Vitamin A content
reports range from 10 - 41.29 mg. per 100 g. Vitamin C content reports
range from 165 - 361.60 mg. per 100 g. [Higher readings for Vitamin C
can be found in raw leaves.]
Comparing the high-end reported protein,
mineral and vitamin content in Chaya leaves (essential amino acids and
antioxidants, too), with the levels in spinach, kale, alfalfa, and so
on, Chaya is understandably hyped as the Maya miracle plant and a super
food. It is eminently healthy and worth eating. As to the many claims
of its medicinal value, I am not going there; many and diverse claims
exist. If Chaya accomplished even 10 per cent of healing powers claimed
for it, it would be notably valuable.
My Chaya cutting indoors
January 2012
Cultivation of the stingless Chaya is
from cuttings. The most common clones usually set no seeds, though one
('Picuda') readily does. Unpruned or uneaten, a Chaya can grow to 20
feet (6m) tall. The plant has a white, sticky sap that can irritate
human skin. Leaves can measure 4 to 15 inches in diameter, on stalks as
long, and be shallowly or deeply lobed. They are dark green on top,
paler green and glossy beneath. According the the cultivar they vary in
shape, though are more or less maple-like. 'Chayamansa' is by far the
most common overall --but not necessarily in U.S. commerce; its leaf
has 5 obovate strongly overlapping lobes. 'Estrella' leaves have 5
spreading, not overlapping, strongly toothed lobes.
'Picuda' leaves
have 5 to 9 narrow
strongly toothed to pinnatifid lobes. 'Redonda'
leaves bear 3 toothless to slightly toothed lobes. I guess my cultivar,
shown in the photos below, is 'Picuda'. The leaf margins have tiny
glands at the teeth, that can secrete a clear sap. Chaya flowers are
small, white, sweetly fragrant, especially at night --to attract moths.
Six mail-order nurseries that offer
Chaya, as of this writing, with prices exclusive of postage, varying
from $7 to 25 per plant: Annie's
Magic Garden, Gardino Nursery,
Kartuz
Greenhouses, Michael Porter at michaels4gardens.com,
Neem
Tree Farms,
Top
Tropicals.
Some of the information above was kindly
provided by Dr. Jeffrey Ross-Ibarra of UC Davis. If you seek additional
data on Chaya, I advise that you consult a published journal article of
16 pages that goes into much valuable detail about the plant, and
includes an extensive bibliography: The Ethnobotany of Chaya
(Cnidoscolus
aconitifolius ssp. aconitifolius
Breckon): A Nutritious
Maya Vegetable by Jeffrey Ross-Ibarra and Alvaro
Molina-Cruz Economic
Botany 56(4): 350-365. (2002).
About Arthur
Lee Jacobson
A lifelong Seattle resident, Arthur developed a passion for plants at
17 and has made his living growing, photographing, and writing about
plants. He is a rare expert who can speak about wild plants, garden
plants, and house plants.
Arthur has a special interest in edible plants, and, in his field guide
Wild Plants of Greater Seattle, he includes comments on the edibility,
taste, and uses of plants found in the city.
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