Common Name: American Holly

General Information

Ilex opaca is an evergreen shrub to small tree that generally grows around 4 - 9 metres tall, though there are records oftrees reaching 30 metres in the past[].
The plant is harvested from the wild for local use as a food, medicine and source of materials. It is commonly grown as an ornamental, where it makes an excellent hedge, and is particularly valued for its evergreen leaves and winter display of red berries.
Ilex opaca has a wide range, is often common within that range, and there are no specific threats. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2018)[].

Known 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[, , ].
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[].
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)[]. 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)

Botanical References

, ,

Range

Central and eastern N. America - Missouri to New York and Massachusetts, south to Texas and Florida

Habitat

Grows in a variety of soil types, but it is generally found in deep moist bottomlands[]. Moist woods, hedges and fields[, ].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	6.00 m
Growth Rate	Slow
Pollinators	Bees
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

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[].
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[]. Plants are fairly wind-resistant[].
A slow-growing and long-lived species in the wild[], but it does not thrive or fruit well in British gardens[]. Plants do not thrive in a maritime climate[]. There are many named forms, selected for their ornamental value[, ].
The leaves remain on the plant for about 3 years, falling in the spring[].
Flowers are produced on the current year's growth[].
Resents root disturbance, especially as the plants get older[]. 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[].
Plants are very tolerant of pruning and can be cut right back into old wood if required[].
A dioecious species - both male and female forms must be grown if fruit and seed are required.

Edible Uses

The roasted leaves are used as a tea substitute[, , ]. They do not contain caffeine[]. The drink was a very popular tea substitute during the American Civil war[].

Medicinal

The berries are laxative, emetic and diuretic[]. They are used in the treatment of children's diarrhoea, colic and indigestion[].

A tea made from the leaves has been used as a treatment for measles, colds etc[, ]. The leaves have also been used externally in the treatment of sore eyes, sore and itchy skin[, ].

A tea made from the bark was once used in the treatment of malaria and epilepsy[]. It has also been used as a wash for sore eyes and itchy skin[].

Agroforestry Uses:

A number of cultivars of this species are used for hedging[]. Fairly wind-resistant, this species is also used in shelterbelt plantings[].

Other Uses

A dye has been made from the berries - the colour is not given[].

Wood - light, tough, not strong, close grained, highly shock resistant, easily worked[, , , ]. A strikingly white wood, it is valued for use in veneers and inlay[]. It weighs 36lb per cubic foot[]. Too small for commercial exploitation, but it is valued for use in cabinet making and the interior finishes of houses[], it is also used for making small items such as tool handles[, , ]. The wood can also be stained to imitate ebony[].

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[, ]. 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.