Ilex serrata
Japanese winterberry
Overview
Ilex serrata is a deciduous shrub reaching 6-12 feet (1.8-3.7 m) tall and 6-10 feet (1.8-3 m) wide, with slender grey stems and dense twiggy branching. Leaves are alternate, elliptic to ovate, 1.5-3 inches (4-8 cm) long, thin, dull mid green, finely toothed along the margin, and hairy on the veins beneath; they turn yellow and drop in October, ahead of most deciduous shrubs. Plants carry male or female flowers, so fruit forms only on female plants with a male within about 50 feet (15 m). Flowers are 0.15 inch (4 mm) across, pale pink to white, in small axillary clusters in May and June. Fruit is a red drupe 0.2-0.25 inch (5-6 mm) across, set closely along the stems in higher numbers than on Ilex verticillata, colouring in September and holding on bare stems into December. The form Leucocarpa carries white fruit. Cut stems in fruit are used in Japanese flower arrangement, where the species is called umemodoki. Leaves yellow between the veins on soils above pH 7.0, and birds strip the fruit from November, which ends the winter colour in some seasons. Berries cause vomiting and diarrhoea on ingestion.
Native Range
Ilex serrata is native to Japan and eastern China, where it grows on damp ground, in thickets, and along stream margins in hill country. It has been grown in Japanese gardens for centuries for the autumn fruit and for cut stems. The species reached Western horticulture in 1893 and is planted through temperate Europe and North America in USDA zones 5-8.Suggested Uses
Planted in groups at 6-8 foot (1.8-2.4 m) spacing in damp borders, on pond margins, and in mixed shrub plantings across USDA zones 5-8, with one male plant for every 6-10 females. Fruited stems are cut in October and November for arrangements and hold their berries 2-3 weeks in water. Berries feed thrushes, waxwings, and mockingbirds from November, and the twiggy structure gives nesting cover.How to Identify
Appearance
Size & Dimensions
Height6' - 12'
Width/Spread6' - 10'
Reaches mature size in approximately 10 years
Bloom Information
Flowering runs 2-3 weeks in May and June, on growth made earlier the same season. Flowers are 0.15 inch (4 mm) across in pale pink to white clusters at the leaf axils, with male plants carrying more flowers per cluster than female plants. Bees move pollen between plants, and one male covers 6-10 females within 50 feet (15 m). Fruit colours from September, 14-16 weeks after flowering.
Detailed Descriptions
Flower Description
Pale pink to whiteFoliage Description
Dull mid green turning yellow in autumnGrowing Conditions
Sun Requirements
Requires 4-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Fruit set is heaviest at 6 or more hours of direct sun, and plants in shade below 4 hours carry scattered berries on drawn-out stems. Acid soil at pH 5.0-6.5 that holds moisture suits the roots, including ground that floods for short periods, while interveinal yellowing follows above pH 7.0. Water at 1-1.5 inches (25-38 mm) per week through the growing season, since the shallow roots dry out in sandy soil. A slow-release fertilizer for acid-loving plants in early spring covers the year's growth. Few pests trouble the species, and leaf spot follows on crowded plants in wet summers. Plants come through winter temperatures to -20F (-29C) without stem damage.Pruning
Pruning is carried out in late winter, before growth resumes, taking out dead wood and thinning crowded stems to open the framework. Flowers and fruit form on the current season's growth, so shortening stems by up to a third does not remove the coming crop. Cutting a third of the oldest stems to the base each year renews plants that have thickened at the centre. Stems cut for indoor use in October come from the outer canopy, which is replaced the following season.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
early spring
Container Growing
✓ Suitable for container growing
Minimum container size: 15 gallons