Common Name: Japanese Holly

General Information

Ilex crenata is an evergreen shrub or small tree with a very dense, rigid, compact habit; it usually grows around 5 - 10 metres tall[, ].
The plant is possibly harvested from the wild for local use as a food. A very ornamental plant, it is often grown in gardens where it can be used as a hedge. There are several named varieties.

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

E. Asia - Nepal, northeast India, Myanmar, southern and eastern China, Japan, Korea, northern Vietnam.

Habitat

Thickets, woods and wet places in lowland and mountains all over Japan[].

Properties

Edibility Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	5.00 m
Growth Rate	Slow
Pollinators	Bees
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

Plants are hardy to about -20°c[].
Ilex species generally tolerate most soils that are not water-logged[]. Prefers a moist loamy soil[]. Fairly slow growing.
A number of named varieties have been selected for their ornamental value[].
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[]. Any transplanting is best done in May or, preferably, in September.
Dioecious. Male and female plants must be grown if fruit and seed is required.

Edible Uses

Fruit[, ]. No further details are given, but some caution is advised[].The fruit is about 5mm in diameter[].

Medicinal

None known

Agroforestry Uses:

Very amenable to trimming, this species is often grown as a hedge in N. America and Japan. It can also be used in topiary[].

Other Uses

An extract of the whole plant is used as an ingredient in commercial cosmetic preparations as a skin conditioner[].

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.