American Holly (Ilex opaca Aiton)

Growth and Attributes

Reproduction: requires male and female plants ^{(TWC Staff, 2015).} It requires a ratio of 3 females per each male plant to successfully produce fruit.

Pollinators: It is pollinated by Henry’s Elfin butterflies and honey bees ^{(Ilex opaca, n.d.).}   

Habitat: shaded rich forest (under the canopy), bottom-lands, streams, rivers, swamp margins and coastal dunes ^{(Ilex opaca, n.d.; TWC Staff, 2015)}  

Distribution: Eastern and central United States; see: USDA Distribution Map^{(Ilex opaca, n.d.)}.

Cultivation:  Grows in full sun to partial shade. It can grow in a wide variety of soils as long as they are moist, well drained, and acidic. It can’t grow in saturated soils (ex. Clay soils) nor in soils with high pH. According to the soil pH, the leaf changes color – for ex., in alkaline soils, the leaves are yellow ^{(Ilex opaca, n.d.; TWC Staff, 2015; American Holly, 2023).}

Conservation status: Least concern ^{(Ilex opaca, 2023)}

Ecosystem value: feeds birds and small mammals, shelters nests, butterflies’ larvae and bees ^{(Ilex opaca, n.d.; TWC Staff, 2015)} 

Human uses: ornamental, shade and hedges.  The wood is used for several items including furniture ^{(Ilex opaca, n.d.; TWC Staff, 2015)} 

Pests: holly leaf miner holly leaf miner leaf damage,  mites, whitefly, and scale.  Diseases include:  leaf spot, American holly rust, leaf rot, tar spot*, black mildew and powdery mildew (Ilex opaca, n.d.; Pettis, 2021) 

^{* The image of tar spot is not of an American Holly, but this disease is still common in that species and presents similarly.}

Unique characteristics:  Resistant to air pollution and clay soil.  It is the only native U.S. holly with spiny green leaves and bright red drupes. Is slow growing._{(Ilex opaca, n.d.; American Holly, 2023; TWC Staff, 2015)}

Toxicity: It is toxic to humans and other animals if consumed _{(Ilex opaca, n.d.; American Holly, 2023; TWC Staff, 2015)} 

Resistant to deer? Yes

Wetland plant status:  there are 2 wetland regions in VA:  

• Mountains and Piedmonts – the American holly is Facultative upland (FACU) in the mountains and piedmonts regions
• Atlantic and Gulf Coastal Plain – the American holly is Facultative (FAC) for the Atlantic and Gulf Coastal Plain

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Recommended Reading

Global Biodiversity Information Facility (GBIF) Listing   

Digital Atlas of the Virginia Flonra Species Distribution Map  

Fact Sheet  

Native Trees and Shrubs for Pollinators  

References

Ilex opaca.  (2023, July 5^th). In Wikipedia.  https://en.wikipedia.org/wiki/Ilex_opaca 

TWC Staff. (2015, November, 12). Ilex opaca Aiton.  Ladybird  Johnson Wildflower center.  https://www.wildflower.org/plants/result.php?id_plant=ILOP 

Ilex opaca.  (n.d.).  North Carolina Extension.   https://plants.ces.ncsu.edu/plants/ilex-opaca/ 

Ilex opaca. (n.d.). Missouri Botanical Garden. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=k640 

Ilex opaca. (n.d.). U.S. Army Corps of Engineers.    https://wetland-plants.sec.usace.army.mil/nwpl_static/v34/species/species.html?DET=001100# 

USDA NRCS Plant Materials Program, (2002, Feb 5). Plant Fact Sheet American Holly Ilex opaca Ait. USDA NRCS.  https://plants.usda.gov/DocumentLibrary/factsheet/pdf/fs_ilop.pdf 

Yale Nature Walk, American Holly, 2023.  Yale University.  https://naturewalk.yale.edu/trees/aquifoliaceae/ilex-opaca/american-holly-91 

^{Coauthored by Monica Marcelli & Adrian Hagarty, 2023.}