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Common Name: Japanese Holly
Ilex crenata is an evergreen shrub that can grow up to 5.00 metres tall.
It is harvested from the wild for local use as a food and source of materials.
Although no specific reports of toxicity have been seen for this species, the fruits of at least some members of this genus contain saponins and are slightly toxic. They can cause vomiting, diarrhoea and stupor if eaten in quantity[
Although poisonous, saponins also have a range of medicinal applications and many saponin-rich plants are used in herbalism (particularly as emetics, expectorants and febrifuges) or as sources of raw materials for the pharmaceutical industry. Saponins are also found in a number of common foods, such as many beans.
Saponins have a quite bitter flavour and are in general poorly absorbed by the human body, so most pass through without harm. They can be removed by carefully leaching in running water. Thorough cooking, and perhaps changing the cooking water once, will also normally remove most of them. However, it is not advisable to eat large quantities of raw foods that contain saponins.
Saponins are much more toxic to many cold-blooded creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc in order to stupefy or kill the fish and make them easy to catch[
E. Asia - China, Japan, Korea.
Thickets, woods and wet places in lowland and mountains all over Japan[
Succeeds in most soils so long as they are not water-logged[
]. Prefers a moist loamy soil[
]. Fairly slow growing.
Plants are hardy to about -20°c[
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.
]. No further details are given, but some caution is advised[
].The fruit is about 5mm in diameter[
Very amenable to trimming, this species is often grown as a hedge in N. America and Japan. It can also be used in topiary[
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.