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Aquifoliaceae FAMILY Least Concern

Ilex opaca

Ilex opaca

Edibility
2/5
Medicinal
2/5

Safety & Hazards

Although no specific reports of toxicity have been seen for this species, Ilex species in general contain several potentially toxic compounds, particularly saponins, glycosides and triterpenoids. These compounds also often have a range of potential health benefits[1, 2, 3]. The berries are usually the part of the plant most likely to be toxic, though the degree of toxicity is usually low. Their bitter flavour usually prevents a person eating more than one or two, but even a small handful of the fruit eaten by a healthy adult is unlikely to cause more than feelings of nausea that can lead on to vomiting and diarrhoea[2]. The compounds in the leaves are particularly interesting. The leaves of many Ilex species around the world are commonly used to make health-promoting teas that, when drunk on a regular basis, help to regulate bodily functions and can reduce the risk of heart disease, lower blood-cholesterol levels etc (See Ilex paraguariensis or Ilex kaushue for examples)[3]. Even these teas, however, if taken in very concentrated doses, can act as a laxative or cause vomiting. Indeed, several species are used by traditional peoples to induce vomiting as a means of purifying the body (see Ilex guayusa or Ilex vomitoria for examples)

Cultivation Details

HabitEvergreen Shrub
GrowthSlow

Ilex opaca is a very cold-hardy plant, known to tolerate winter temperatures as low as -23°c in parts of its range, although -18°c is the average for the species. The mean annual precipitation throughout its range is 1,020 - 1,650mm, but with over 2,030mm in some areas[4]. Tolerant of most soils so long as they are not water-logged, succeeding in thin mountain soils and near sterile soils on sandy beaches, though growing best on rich, moist but well-drained soils[4]. Plants are fairly wind-resistant[5]. A slow-growing and long-lived species in the wild[6], but it does not thrive or fruit well in British gardens[7]. Plants do not thrive in a maritime climate[8]. There are many named forms, selected for their ornamental value[7, 5]. The leaves remain on the plant for about 3 years, falling in the spring[9]. Flowers are produced on the current year's growth[6]. Resents root disturbance, especially as the plants get older[10]. It is best to place the plants into their permanent positions as soon as possible, perhaps giving some winter protection for their first year or two[PFAF]. Plants are very tolerant of pruning and can be cut right back into old wood if required[8]. A dioecious species - both male and female forms must be grown if fruit and seed are required.

Propagation

Seed - best sown as soon as it is ripe in the autumn in a cold frame. It can take 18 months to germinate. Stored seed generally requires two winters and a summer before it will germinate and should be sown as soon as possible in a cold frame. Scarification, followed by a warm stratification and then a cold stratification may speed up the germination time[11, 12]. The seedlings are rather slow-growing. Pot them up into individual pots when they are large enough to handle and grow them on in light shade in a cold frame for their first year. It is possible to plant them out into a nursery bed in late spring of the following year, but they should not be left here for more than two years since they do not like being transplanted. Alternatively, grow them on in their pots for a second season and then plant them out into their permanent positions in late spring or early summer. Give them a good mulch and some protection for their first winter outdoors. Cuttings of almost ripe wood with a heel, August in a shaded position in a cold frame. Leave for 12 months before potting up. Layering in early autumn. Takes 2 years. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Ilex+opaca>

Pollinators

Bees

References

  1. [1]Illustrated Flora of North Central Texas — Diggs, Jnr. G.M.; Lipscomb. B. L. & O'Kennon. R. J · Botanical Research Institute, Texas. · 1999 · http://artemis.austincollege.edu/acad/bio/gdiggs/NCTXpdf.htm · ISBN 1-889878-01-4 ↩︎An excellent flora, which is also available on-line.
  2. [2]Poisonous Plants of North Carolina — http://www.ces.ncsu.edu/depts/hort/consumer/poison/poison.htm ↩︎An excellent concise but comprehensive guide to toxic plants that grow in N. Carolina. It lists even those plants that are of very low toxicity, including several well-known food plants such as carrots and potatoes.
  3. [3]Genus Ilex L.: Phytochemistry, Ethnopharmacology, and Pharmacology — Fan Yi, Xiao-ling Zhao, Yong Peng, Pei-gen Xiao · 2016 · http://10.1016/S1674-6384(16)60044-8 ↩︎
  4. [4]IUCN Red List of Threatened Species — http://www.iucnredlist.org/ ↩︎A list of plants under threat and facing possible extinction, usually with brief details of the threats and information on habitat.
  5. [5]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  6. [6]The Complete Trees of N. America. Field Guide and Natural History. — Elias. T. · Van Nostrand Reinhold Co. · 1980 · ISBN 0442238622 ↩︎A very good concise guide. Gives habitats, good descriptions, maps showing distribution and a few of the uses. It also includes the many shrubs that occasionally reach tree proportions.
  7. [7]Ornamental Shrubs, Climbers and Bamboos. — Thomas. G. S. · Murray · 1992 · ISBN 0-7195-5043-2 ↩︎Contains a wide range of plants with a brief description, mainly of their ornamental value but also usually of cultivation details and varieties.
  8. [8]The RHS Gardener's Encyclopedia of Plants and Flowers — Brickell. C. · Dorling Kindersley Publishers Ltd. · 1990 · ISBN 0-86318-386-7 ↩︎Excellent range of photographs, some cultivation details but very little information on plant uses.
  9. [9]Manual of the Trees of N. America. — Sargent. C. S. · Dover Publications Inc. New York. · 1965 · http://www.biodiversitylibrary.org/ · ISBN 0-486-20278-X ↩︎Two volumes, a comprehensive listing of N. American trees though a bit out of date now. Good details on habitats, some details on plant uses. Not really for the casual reader. It can be downloaded from the internet.
  10. [10]Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. — Bean. W. · Murray · 1981 · ISBN - ↩︎A classic with a wealth of information on the plants, but poor on pictures.
  11. [11]Propagation of Trees, Shrubs and Conifers. — Sheat. W. G. · MacMillan and Co · 1948 · ISBN - ↩︎A bit dated but a good book on propagation techniques with specific details for a wide range of plants.
  12. [12]Hardy Woody Plants from Seed. — McMillan-Browse. P. · Grower Books · 1985 · ISBN 0-901361-21-6 ↩︎Does not deal with many species but it is very comprehensive on those that it does cover. Not for casual reading.
  13. [13]Gray's Manual of Botany.Eighth Edition — Fernald. M. L. · American Book Co.; New York · 1950 · ISBN 0442222505 ↩︎A bit dated but a good and concise flora of the eastern part of N. America.
  14. [14]Shrubs. — Phillips. R. & Rix. M. · Pan Books · 1989 · ISBN 0-330-30258-2 ↩︎Excellent photographs and a terse description of 1,900 species and cultivars.
  15. [15]Food Plants of the N. American Indians. — Yanovsky. E. · U.S. Depf of Agriculture. · ISBN - ↩︎A comprehensive but very terse guide. Not for the casual reader.
  16. [16]Plants for Human Consumption. — Kunkel. G. · Koeltz Scientific Books · 1984 · ISBN 3874292169 ↩︎An excellent book for the dedicated. A comprehensive listing of Latin names with a brief list of edible parts.
  17. [17]Food Plants in the Americas: A Survey of the Domesticated, Cultivated, and Wild Plants Used for Human Food in North, — Kermath B.M.; Bennett B.C.' Pulsipher L.M. · 2014 ↩︎A pre-publication draft of an amazing, on-going work first started in 1985. It contains information on more than 3,900 taxa from the Americas - from Arctic regions to the Tropics
  18. [18]Cornucopia - A Source Book of Edible Plants. — Facciola. S. · Kampong Publications · 1990 · ISBN 0-9628087-0-9 ↩︎Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.
  19. [19]A Field Guide to Medicinal Plants. Eastern and Central N. America. — Foster. S. & Duke. J. A. · Houghton Mifflin Co. · 1990 · ISBN 0395467225 ↩︎A concise book dealing with almost 500 species. A line drawing of each plant is included plus colour photographs of about 100 species. Very good as a field guide, it only gives brief details about the plants medicinal properties.
  20. [20]Native American Ethnobotany — Moerman. D. · Timber Press. Oregon. · 1998 · ISBN 0-88192-453-9 ↩︎Very comprehensive but terse guide to the native uses of plants. Excellent bibliography, fully referenced to each plant, giving a pathway to further information. Not for the casual reader.
  21. [21]Trees of Central Texas. — Vines. R. A. · University of Texas Press · 1987 · ISBN 0-292-78958-3 ↩︎A good concise guide, it gives details of habitats and some of the uses of trees growing in Texas.
  22. [22]Economic Botany. — Hill. A. F. · The Maple Press · 1952 · ISBN - ↩︎Not very comprehensive, but it is quite readable and goes into some detail about the plants it does cover.
  23. [23]An Illustrated Flora of the Northern United States and Canada — Britton. N. L. Brown. A. · Dover Publications. New York. · 1970 · ISBN 0-486-22642-5 ↩︎Reprint of a 1913 Flora, but still a very useful book.
  24. [PFAF]Plants for a Future — pfaf.org ↩︎