Ilex verticillata Seeds | Winterberry
LATIN NAME: Ilex verticillata
COMMON NAME: Winterberry
Plant Profile
Winterberry is the holly that gives up its leaves, and that single decision is what makes it the most spectacular shrub of the winter garden. It is a deciduous shrub of swamp edges and wet thickets in eastern North America, usually one to three metres tall, with a loose, suckering habit that builds into a thicket rather than a neat specimen. The leaves are plain, oval and finely toothed, unremarkable for most of the year and gone by November.
What remains is the fruit: dense clusters of round berries set tight against the bare grey stems, holding colour well into winter and often into February. The berries are the size of small peas and can be fire-engine red, orange or, in a few selections, gold. Flowers are small, greenish and inconspicuous, and they open in June, which is late for a holly and late enough to miss most spring frosts.
Science & Biotechnology
The species is dioecious, with male and female flowers on separate plants, and this shapes everything about how it is grown and studied. A female clone will fruit only if a male of the same species flowers within roughly fifty metres, and nurseries sell named males for exactly that reason. The fruit is a drupe with four to six stones, and the seed inside carries a deep embryo dormancy that takes two winters to break in nature; germination in the second spring is the rule, not the exception.
Winterberry also hybridises freely with the Japanese Ilex serrata, and a number of the better garden forms are the result, which is why some of them show intermediate leaf shape and earlier colour. Research on the genus has used the species in studies of wetland shrub ecology and of bird-mediated seed dispersal, since the fruit is eaten mainly by thrushes and waxwings that move seed along stream corridors.
Uses & Benefits
This is a plant for the winter garden, pure and simple. Planted in a group with a male among them, the females carry so much fruit that the stems look painted, and the effect against a dark hedge or a grey sky is stronger than any evergreen holly. It is also one of the best shrubs for wet ground, tolerating seasonal flooding and heavy clay where most ornamentals sulk, and it will grow in ordinary garden soil as long as it does not dry out completely.
The fruit is not for people; it is mildly toxic and laxative, and it is best left to the birds, which strip the bushes in late winter once the berries have softened. Cutting branches for indoor decoration is one of the real pleasures of the plant, since the berries hold on the stem for weeks without dropping, and a single armful will carry a room through the darkest part of the year.
Growing from Seed
Sow cleaned seed, and expect to wait. The seed needs a warm, moist period of about three months followed by three months of cold, and even then germination is staggered over the following spring. A simpler route is to sow fresh fruit in a pot outdoors in autumn and leave the pot exposed to the weather for two winters, which lets the sequence happen naturally.
Use an acid, humus-rich compost and keep it wetter than you would for most shrubs; winterberry resents drying out at any stage. Seedlings vary in berry colour and in fruit density, so named clones are propagated from cuttings. If you want a particular form, buy a female clone and a compatible male rather than sowing seed, and plant them within a few metres of each other rather than at opposite ends of the garden.
Our Take
The best berrying shrub for wet ground and winter colour, provided you plant a male nearby. Two plants, one male and one female, are the whole secret to a winter of berries.
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