| EGardening Last modified February 09, 2009 |
|
|
Tomatillo
|
 Image source: Hernández & Rivera |
In my garden, I grow three members of the ground cherry genus, Physalis. This Greek word, chosen by Linnaeus in 1753, describes the unusual inflated calyx or bladder the envelopes the berries of these plants. Most are familiar with the decorative papery orange calyx of the highly ornamental Chinese lantern (P. alkekengi L.) widely grown in Canadian gardens. While I enjoy this Eurasian perennial herb, it must be carefully confined to prevent errant runners from taking over the garden. Other members of this clan are less problematic and although less attractive they offer tastier treasures.
The vast majority of the ground cherry species originate in Mexico, and a few perennial species range naturally to Canada. These somewhat weedy types (the clammy, longleaf and Virginia ground cherries) can be effective for naturalizing sites. A favorite of short-tongued bees, my diminutive clammy ground cherry, is quietly spreading in a corner of my native restoration garden, providing berries for birds, mice and chipmunks. But, those berries are bitter. There are far more delectable species. While some may prefer the sweet cape gooseberry (P. peruviana) and the strawberry tomato (P. pubescens var integrifolia syn P. pruinosa), my favourtie is the Mexican tomatillo or husk tomato, (P. philadelphica Lam. syn P. ixocarpa).
The word tomatillo is Spanish for small tomato. The name is derived from the Nahuatl (Aztec) word, tomatl - from tomana, meaning to swell and atl, meaning water. For centuries in Mesoamerica, the ground cherries have been a staple. “Physalis sp. used as food have been found in excavations in the valley of Tehuacán (900 BC–AD 1540). In pre-Hispanic times in Mexico, it was preferred far more than the tomato (Lycopersicon sp.),” (Montes-Hernández & Aguirre-Rivera, 1994). In the 16th century, Spanish explorers were introduced to the tomatillo and its sweeter sisters, the Cape gooseberry (P. peruviana) and the strawberry tomato (P. pubescens var integrifolia syn P. pruinosa). Along with tomatoes, potatoes and capsicum, these edible nightshades (Solonaceae), were then transported to Asia and Europe.
Given their resemblance to plants like the Deadly Nightshade, (Atropa belladonna) acceptance was slow, and the ground cherries were never widely cultivated in Eurasia. Like most members of Solonaceae, ground cherries contain varying amounts of poisonous alkaloids, particularly in their leaves. Unripe Physalis berries can contain unsafe levels of solanine a glycoalkaloid that can cause gastrointestinal distress or worse, (Nelson et al . 2006, p. 238). There is great variability in the genus and this may have led to unpleasant surprises.
That variability has contributed to considerable taxonomic confusion. For instance, the accepted scientific name for tomatillo is Physalis philadelphica Lam., though it is often described as P. ixocarpa Brot., and a debate is ongoing (ITIS, 2009; Escobar-Guzman et. al., 2009). Generally however, it is agreed that the wild tomatillo is a sprawling annual plant from 15 to 60 cm tall (staked they can reach 1.5m). It has almost hairless, alternate, ovate leaf blades with toothed edges about 6-7cm in length. Single saucer-shaped yellowish flowers, 10-18mm wide, emerge from leaf axils with petal lobes that reflex (fold back) at anthesis (maturity). The anthers are bluish and about 3mm long. If fertilized, the 10 ribbed, 2-3 cm, calyx will fill with a pulpy sticky ovate fruit, (Waterfall, 1967, p 213). Ready for the picking.
The ripe fruit is a berry usually green in color although yellow, orange and purple varieties are available. At maturity, the papery husk may split and the fruit fall to the ground. It takes about 5 to 8 weeks of development in the commonly cultivated variety “Rendidora,” But there are hundreds of other possibilities including: the sweet little, 2.5cm, green “Zuni” (65days); the tarter medium-sized, 5cm, “Purple” (65days); the large, 10cm “Gigante;” (100days); and the fruity, golden “Pineapple” (70days), (Reimer Seeds, 2003). The heritage seeds organization, Seeds of Diversity, provides a good list of Canadian tomatillo seed suppliers on their website - www.seeds.ca .
Although it is cultivated year-round in Mexico, here in Canada, tomatillos should be sown in the garden after danger of frost. In the GTA, that is around the first week of May. Starting plants indoors, 4 weeks earlier, will provide for a longer crop season. Tomatillos grow like tomatoes. They are not too particular about soil, as long as it is well drained. They do best in sun, but can tolerate partial shade. Seeds should be sown in hills (1cm deep) about 40-60 cm apart in rows wide enough to work and provide for good air circulation (0.75 to 1.5m in production fields), (Smith, Jimenez & Cantwell, 1999). Researchers have found that Physalis ixocarpa can not pollinate itself, thus a tomatillo plant will not fruit properly if grown singly in small gardens or in an isolated container, (Pandey, 1957). Commercial growers often use irrigation systems to supply the 2.5 to 4 cm of water required for optimal growth, (Smith, Jimenez & Cantwell, 1999; Everhart, 2003). A well prepared bed with organic matter, such as composted manure, should need little amendment. Specific recommendations for moderate fertilization procedures for commercial growers are presented in the Smith, Jimenez and Cantwell report on Tomatillo production in California, (1999)
Protected by its paper husk, the tomatillo is bothered by few pests and diseases. If slugs and snails are problematic, the plants should be lifted off the ground with cages or stakes. Ensuring proper air circulation, with proper plant spacing, should reduce the potential for powdery mildew or other foliage blights and wilts. Physalis species are susceptible to several insects that affect tomatoes such as the tomato hornworm and false potato beetle, as well as cucumber beetles and flea beetles. These can be removed by hand or controlled before fruit sets with sprays of Bt (Bacillus thuringiensis). Insecticidal soaps and high pressure water sprays are recommended for the occasional aphid, white fly or spider mite outbreak, (.Sciarappa, 2004). Insects may spread certain viruses like tomato chlorosis virus or physalis yellow mottle virus, although there are no reports of these associated with tomatillo in Ontario, (Valverde, 1993; Trenato, 2007).
This summer vegetable is a bit ungainly. But the reward for entertaining this unruly guest is an abundance of large edible tomato-like berries from August until frost. 65-200 berries per plant is typical. Fruit will continue to ripen after picked and can be stored in a cool dry place for several months. Before frost, the entire plant can be pulled up and hung upside-down in a dry place until the remaining fruit are needed, (Morton, 1987). Tomatillos are higher in both sugars and acids than tomatoes and are slightly more caloric, 30kcal/100g compared to 20kcal/100g (Bock 1995; Cantell, 1992; Escobar-Guzman et. Al. 2009). There are several recipes for fresh and cooked green chili sauces below. Here is one to start you off.
|
Tomatillo Salsa Verde Recipe (Makes 3 cups) Ingredients
1 1/2 lb tomatillos (about 30 fruit depending on variety) Remove papery husks from tomatillos and rinse well. Place tomatillos in a saucepan. Cover with water and bring to a boil. Simmer for 5 minutes. (Alternatively, they can also be roasted on the grill/broiler which blackens the skin and adds great flavour). Place drained tomatillos along with the other ingredients in a food processor and pulse until finely chopped and mixed. Season to taste with salt. Cool. Serve with chips or as an accompaniment to Mexican dishes. |
So look for tomatillos in you seed catalogue and enjoy the unusual and tasty little tomatl.
More Recipes for Salsa Verde
-
Chef to Chef http://chef2chef.net/recipes/search_result.php?search=tomatillo&sa=Search
-
Authentic Salsa Verde http://www.authenticsalsarecipes.com/salsa-verde/
Atropa belladonna. (2009, January 22). In Wikipedia, the free encyclopedia. Retrieved on January 23, 2009, from http://en.wikipedia.org/wiki/Atropa_belladonna
Bateman, Melanie. (2006). Impact of Plant Suitability, Biogeography, and Ecological Factors on Associations between the Specialist Herbivore Heliothis subflexa G. (Lepidoptera: Noctuidae) and the Species in its Host Genus, Physalis L. (Solanaceae), in West-Central Mexico. Dissertation. North Carolina State University. Retrieved January 25, 2009, from http://www.lib.ncsu.edu/theses/available/etd-05182006-142927/unrestricted/etd.pdf
Bock, M. Sanchez-Pilcher, J. McKee, L. Melchor-Ortiz, Z. (1995, Sept.) Selected nutritional and quality analyses of tomatillos Plant Foods and Human Nutrition. 48[2] pp. 127-33.
Callen, E. O. (1965, Oct.-Dec.). Food Habits of Some Pre-Columbian Mexican Indians. Economic Botany. 19[4] pp. 335-343. Retrieved January 23, 2009, from http://www.jstor.org/stable/4252642
Cantwell, Marita. (2006). Tomatillo (Husk Tomato) Postharvest Technology Research & Information Center University of California. Retrieved January 23, 2009, from http://postharvest.ucdavis.edu/Produce/ProduceFacts/Veg/tomatillo.shtml
Cantwell, M., J. Flores-Minutti and A. Trejo-González. (1992). Developmental changes and postharvest physiology of tomatillo fruits (Physalis ixocarpa Brot.). Scientia Horticulturae. 50. pp 59-70. Retrieved January 25, 2009, from http://postharvest.ucdavis.edu/datastorefiles/234-572.pdf
D'Arcy, William. (1986). Introduction to Origin and Distinctions of Domesticates. p. 379-382. In: W.G. D'Arcy (ed.). Solanaceae, biology and systematics. Columbia Univ. Press, New York. Retrieved January 23, 2009, from http://books.google.com/books?id=fCt3zd8cGaIC&printsec=frontcover&dq=Solanaceae
Encycloweedia. (n.d.). Tomatillo. California Dept. of Food and Agriculture. Retrieved January 25, 2009, from http://www.cdfa.ca.gov/PHPPS/IPC/weedinfo/physalis.htm
Everhart, E.; Haynes, C. and R. Jauron. (2003, April) Tomatillos. Home Gardening. Iowa State University. Retrieved January 25, 2009, from http://www.extension.iastate.edu/Publications/PM1895.pdf
Escobar-Guzman, R.; Hernandez-Godinez, F.; de la Vega, O.; Ochoa-Alego, N. (2009). In vitro embryo formation and plant regeneration from anther culture of different cultivars of Mexican husk tomato (Physalis ixocarpa Brot.). Plant Cell Tiss Organ Cult. 96:181–189.
Hanelt, P.; Buttner, R.; Mansfeld, R.; R. Kilian. (2001). Mansfeld's Encyclopedia of Agricultural and Horticultural Crops. Springer-Verlag Publishers. Excerpts retrieved January 23, 2009, from http://books.google.ca/books?hl=en&id=10IMFSavIMsC&dq=Mansfeld's+Encyclopedia
Harper, Douglas. (2001, Nov.). Tomato. In Online Etymology Dictionary. Retrieved January 23, 2009, from http://www.etymonline.com/index.php?search=tomato&searchmode=none
Heiser, Charles B. (1965, Aug.). Cultivated Plants and Cultural Diffusion in Nuclear America. American Anthropologist.. 67[4] pp. 930-949. Retrieved January 23, 2009, from http://www.jstor.org/stable/668774
Hilty, John. (2002-2008). Clammy Ground Cherry. In [Online Guide] Illinois Wildflowers. Retrieved January 23, 2009, from http://www.illinoiswildflowers.info/prairie/plantx/cl_cherryx.htm
Hu Jin-Yong; Saedler, Heinz. (2007) Evolution of the inflated calyx syndrome in Solanaceae. Molecular biology and evolution. 24[11] pp.2443-53
Hudson, W. D. (1986). Relationships of Domesticated and Wild Physalis philadelphica
416-432 In: W.G. D'Arcy (ed.). Solanaceae, biology and systematics. Columbia Univ. Press, New York. Retrieved January 23, 2009, from http://books.google.com/books?id=fCt3zd8cGaIC&printsec=frontcover&dq=Solanaceae
ITIS (2009). Physalis. In the Integrated Taxonomic Information System (ITIS). Retrieved January 23, 2009, from http://www.itis.gov
Pandey, Kamla (1957, Dec.). Genetics of Self-Incompatibility in Physalis ixocarpa Brot. American Journal of Botany, 44[10] pp. 879-887
Maynard, D. (1993). Potential for Commercial Production of Tomatillo in Florida. Proc. Fla. State Hort. Soc. 106. pp. 223-224
Menzel, M.Y. (1951). The cytotaxonomy and genetics of Physalis. Proc. Amer. Phil. Soc. 95. pp. 132-183.
Menzel, M.Y. (1957). Cytotaxonomic studies of Florida coastal species of Physalis. Amer. Phil. Soc. 1957. pp. 262-266.
Montes-Hernández, S., and J.R. Aguirre Rivera. (1994). Tomatillo, husk-tomato. J.E. Hernándo Bermejo and J. León (eds). Neglected Crops: 1492 from a Different Perspective. Plant Production and Protection Series No. 26. FAO, Rome. Retrieved January 23, 2009, from http://www.fao.org/docrep/T0646E/T0646E0d.htm
Morales, M. (2001). Tomatillo: Evaluation of a Potential New Ethnic Vegetable Crop for Indiana. Purdue Hort. Extension Service. Retrieved January 26, 2009, from http://www.hort.purdue.edu/hort/ext/veg/MWVVT2001/html/INMorales2001Tomatillo.htm
Moriconi, D.N., Rush, M.C., Flores, H. (1990). Tomatillo: A potential vegetable crop for Louisiana. p. 407-413. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR. Retrieved January 24, 2009, from http://www.hort.purdue.edu/newcrop/proceedings1990/v1-407.html
Morton, J. (1987). Mexican Husk Tomato. p. 434–437. In: Fruits of warm climates. Julia F. Morton, Miami, FL. Retrieved January 24, 2009, from http://www.hort.purdue.edu/newcrop/morton/mexican_husk_tomato.html
NatureServe. (2008). Physalis. In NatureServe Web Service. Arlington, VA. U.S.A. Retrieved January 23, 2009, from http://www.natureserve.org/explorer/servlet/NatureServe?searchSciOrCommonName=physalis&x=0&y=0
Nelson, L., R. D. Shih, M. J. Balick and K. F. Lampe. (2006). Handbook of Poisonous and Injurious Plants, ed. 2. New York: New York Botanical Garden and Springer.
Nutrition facts. (2008, June). Tomatillos, raw The Titi Tudorancea Bulletin Online Nutrition Database. Retrieved on January 24, 2009, from http://www.tititudorancea.com/z/nutrition_facts_physalis_ixocarpa_tomatillos_raw.htm
Tomatoes, red, ripe, raw, year round average. The Titi Tudorancea Bulletin Online Nutrition Database. Retrieved on January 24, 2009, from http://www.tititudorancea.com/z/nutrition_facts_lycopersicon_esculentum_tomatoes_red_ripe.htm
OMAFRA. (2000). Ontario Weeds: smooth ground-cherry. In Ontario Weeds Gallery. Government of Ontario. Retrieved January 24, 2009, from http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/smooth_groundcherry.htm
OMAFRA. (2002). Ontario Weeds: clammy ground-cherry. In Ontario Weeds Gallery. Government of Ontario. Retrieved January 24, 2009, from http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/clammy_groundcherry.htm
Reimer Seeds. (2003). Category: Tomatillo. In the Reimer Seeds Electronic Catalog. Retrieved on January 23, 2009, from http://www.reimerseeds.com/Catalogs/708.pdf
Robertson, John. (2003-2008). physalo-, physal-, physali- In [Online version] Robertson’s Words for a Modern Age. Senior Scribe Publications. Retrieved on January 23, 2009, from http://www.wordinfo.info/words/index/info/view_unit/1659
Sciarappa, William J. (2004, July). Tomatillos. Rutgers Cooperative Research & Extension, NJAES, Rutgers, The State University of New Jersey. Retrieved on January 22, 2009, from http://njaes.rutgers.edu/pubs/download-free.asp?strPubID=FS042
Sparks Mexico. (n.d.). Mexican Husk Tomato. Retrieved January 25, 2009, from http://sparks-mexico.com/costalegre/fruit/tomatillo.htm
Smith, R., M. Jimenez & M. Cantwell. (1999). Tomatillo production in California. Univ. Calif. Div. Agric. Nat. Res. Pub. No. 7246, 2 pp. Retrieved on January 24, 2009, from
http://anrcatalog.ucdavis.edu/pdf/7246.pdf
Trenado, H.; Fortes, I. (2007, June). Physalis ixocarpa and P. peruviana, new natural hosts of Tomato chlorosis virus. European Journal of Plant Pathology. 118[2] pp. 193–196 Abstract Retrieved on January 24, 2009, from http://www.uky.edu/Ag/NewCrops/introsheets/tomatillo.pdf
Valverde R. A.; Can F; Rush M. C. (1993) Yellow mottle of tomatillo (Physalis ixocarpa) caused by physalis mottle virus. Plant pathology 42[4] pp. 657-660
Walker E. and L. Walker. (2009). Tomatillos (Physalis ixocarpa). Growing Taste; [Online] Home Food-Gardening Resource. Retrieved on January 24, 2009, from http://growingtaste.com/vegetables/tomatillo.shtml
Waterfall, U. T. (1967). A taxonomic study of the genus Physalis in North America north of Mexico. Rhodora. 69 pp. 82–120 & 203–329.
Waterfall, U. T. (1958). A taxonomic study of the genus Physalis in North America north of Mexico. Rhodora. 60 pp. 107–173.
Watson, George. (Apr., 1938). Nahuatl Words in American English. American Speech, 13[2] pp. 108-121. Retrieved on January 23, 2009, http://www.jstor.org/stable/451954
Whitson, M.K. and P.S. Manos. (2005). Untangling Physalis (Solanaceae) from the physaloids: a two-gene phylogeny of the Physalinae. Systematic Botany, 30, pp. 216-230.
World Climate. (2008). Toronto Retrieved January 23, 2009, from http://www.worldclimate.com/cgi-bin/data.pl?ref=N43W079+2100+7162401G1
Wu, Z. Y. & Raven, P. H. (Eds.). (1994–). Physalis. In Flora of China Vol. 1 (p. 311). Science Press, Beijing; Missouri Botanical Garden Press, St. Louis. Retrieved January 23, 2009, from http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=125280