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Convex-Leaved Japanese Holly Ilex crenata 'Convexa'

Other Common Name(s):

Phonetic Spelling
EYE-leks kre-NAY-tuh
This plant has low severity poison characteristics.
See below
Description

Convexa Japanese Holly is a handsome evergreen shrub in the Aquifoliaceae family. It is a cultivar of Ilex crenata, or Box Leaved Holly, and is noted for its pea-sized black fruit and leaves, which are convex when viewed from above. It is an extremely dense shrub that does well with heavy pruning and topiary, is very suitable for hedging, and grows up to 8 feet high and twice as wide. The plant flowers in late spring and its fruits ripen in abundance in the fall. The fruits are black and not showy and the leaves are usually smaller than the 'Hetzii' or 'Latifolia' cultivars. It tolerates drought and air pollution, as well as poor, sandy, and clay soils. The plant has a slow growth rate, likes to be in the shade, and does not like alkaline soils. The female plant does produce a heavy crop of fruit in the fall, which can discolor the foliage. With that in mind, some people prefer to plant male Convexa Japanese Holly for the fall and winter foliage, but not the fruit.

Plant in the full sun to partial shade in acidic well-drained soil though it tolerates a wide range of soil types, from moist to dry, including clay. The shrub tolerates drought, shade, air pollution, poor soils, and clay soils and is easy to transplant. It may not thrive in areas with high heat and humidity (USDA zones 8 and 9). The species is dioecious (meaning individual flowers are either male or female, but only one sex is to be found on any one plant, thus both male and female plants must be grown if seed is required). It is pollinated by bees and is not self-fertile.

Diseases, Insect Pests, and Other Plant Problems:

This holly is susceptible to spider mites and iron and nitrogen deficiencies. Alkaline soils will cause the leaves to yellow.

More information on Ilex crenata.

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#evergreen#white flowers#shrub#wildlife plants#green flowers#nectar plant#spring flowers#air pollution tolerant#specialized bees#pollinator plant#black fruits#japanese#poor soils tolerant#sandy soils tolerant#clay soils tolerant#bee friendly
 
Cultivars / Varieties:
Tags:
#evergreen#white flowers#shrub#wildlife plants#green flowers#nectar plant#spring flowers#air pollution tolerant#specialized bees#pollinator plant#black fruits#japanese#poor soils tolerant#sandy soils tolerant#clay soils tolerant#bee friendly
  • Attributes:
    Genus:
    Ilex
    Species:
    crenata
    Family:
    Aquifoliaceae
    Life Cycle:
    Perennial
    Woody
    Recommended Propagation Strategy:
    Seed
    Stem Cutting
    Country Or Region Of Origin:
    East Nepal to Temperate East Asia, Japan and Korea
    Fire Risk Rating:
    medium flammability
    Wildlife Value:
    The small fragrant flowers attract bees. Members of the genus Ilex support the following specialized bee: Colletes banksi.
    Particularly Resistant To (Insects/Diseases/Other Problems):
    Moderately resistant to damage by deer
    Edibility:
    Use caution. Human ingestion of berries can cause minor toxic reaction.
    Dimensions:
    Height: 6 ft. 0 in. - 8 ft. 0 in.
    Width: 6 ft. 0 in. - 14 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Shrub
    Woody Plant Leaf Characteristics:
    Broadleaf Evergreen
    Habit/Form:
    Dense
    Erect
    Multi-stemmed
    Spreading
    Growth Rate:
    Slow
    Maintenance:
    Medium
    Texture:
    Medium
    Appendage:
    Spines
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    Clay
    High Organic Matter
    Loam (Silt)
    Sand
    Soil pH:
    Acid (<6.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Good Drainage
    Moist
    Occasionally Wet
    Available Space To Plant:
    3 feet-6 feet
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    5b, 5a, 6b, 6a, 7b, 7a, 8a, 8b
  • Fruit:
    Fruit Color:
    Black
    Display/Harvest Time:
    Fall
    Fruit Type:
    Berry
    Drupe
    Fruit Length:
    < 1 inch
    Fruit Width:
    < 1 inch
    Fruit Description:
    Abundant globose, berry-like black drupe that is slightly greater than 1/4 inch in length. Only female plants have fruits. Fruits ripen in fall and are not showy.
  • Flowers:
    Flower Color:
    Green
    White
    Flower Inflorescence:
    Cyme
    Flower Value To Gardener:
    Fragrant
    Flower Bloom Time:
    Spring
    Flower Petals:
    4-5 petals/rays
    Flower Size:
    < 1 inch
    Flower Description:
    Non-showy greenish white flowers in spring that form in clusters of 2 to 3 and are 1/4 inch in length. Flowers bloom in late spring. Pistillate cyme, in leaf axils of current season's growth; staminate solitary in leaf axils of current season's growth.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Broadleaf Evergreen
    Leaf Color:
    Green
    Purple/Lavender
    Leaf Feel:
    Glossy
    Leathery
    Smooth
    Waxy
    Leaf Value To Gardener:
    Long-lasting
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Elliptical
    Lanceolate
    Oblong
    Obovate
    Leaf Margin:
    Crenate
    Serrate
    Hairs Present:
    No
    Leaf Length:
    < 1 inch
    Leaf Width:
    < 1 inch
    Leaf Description:
    Leaves are glossy black-green in color and the underside of the leaves are dotted with blackish pellucid glands. The leaf is too small to fit on a fingertip (around a 1/2 inch in length), and is crenate and convex.
  • Bark:
    Bark Color:
    Dark Gray
    Green
    Surface/Attachment:
    Smooth
    Bark Description:
    Smooth, gray-brown or slightly greenish.
  • Stem:
    Stem Color:
    Brown/Copper
    Green
    Stem Is Aromatic:
    No
    Stem Surface:
    Hairy (pubescent)
    Stem Description:
    Stems are green on current season of growth and turn gray-green to gray-brown by year 2 or 3. Young stems are often densely pubescent.
  • Landscape:
    Landscape Location:
    Coastal
    Container
    Lawn
    Patio
    Recreational Play Area
    Slope/Bank
    Walkways
    Landscape Theme:
    English Garden
    Pollinator Garden
    Design Feature:
    Border
    Foundation Planting
    Hedge
    Mass Planting
    Small groups
    Attracts:
    Bees
    Pollinators
    Specialized Bees
    Resistance To Challenges:
    Deer
  • Poisonous to Humans:
    Poison Severity:
    Low
    Poison Symptoms:
    Minor toxicity. Ingestion may cause vomiting, diarrhea, or other illness in humans.
    Poison Toxic Principle:
    Saponins
    Causes Contact Dermatitis:
    No
    Poison Part:
    Fruits