Ilex crenata 'Sky Pencil' (Box-Leaved Holly)

Overview

This is a strictly upright, fastigiate form that is becoming more common at nurseries. It grows to 8' tall, but less than 12" wide. It may be used as a formal accent or container specimen.

Interesting Facts

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Common Names

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Common Names in English:

Box-Leaved Holly, Boxleaf Holly, Japanese Holly, Sky Pencil Upright Japanese Holly

Description

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Genus Ilex

Usually dioecious shrubs or trees . Leaves coriaceous , often spinose and shiny above; stipules caducous . Flowers 4-5-merous, bisexual or unisexual with vestigial remains of either sex. Corolla rotate. Style absent or obsolete , stigma lobed . Drupe fleshy , pyrenes 2-5, rarely more.

400 species, tropical and subtropical areas of both hemispheres. Represented in Pakistan by 2 species (excluding 1 cultivated species) .[1]

Physical Description

ID Features: Alternate leaf arrangement and small marginal serrations separate it from. Buxus sp. which has opposite leaves and no serrations. Dense, rigid, multibranched habit. Lustrous evergreen leaves. Black fruit.

Habit: Fastigiate evergreen shrub . Dense with lots of rigid branches.

Flowers: Dioecious, with male and female plants . Blooms in May into June; not showy. Small, dull white flowers in clusters of 3 to 5 (male). • Bloom Period: April, May. • Flower Color: pale green

Seeds: Fruit: Female plants may produce 0.25" diameter black fruit. Male plants bear no fruit, but are needed as pollinators. Fruit in September - October; often persist until spring . Fruits borne below the foliage and hidden. Fruit is not ornamentally significant.

Foliage: Tiny, narrow, dark green, shallowly toothed , oval to ovate glossy evergreen . • Summer foliage: Dark green, lustrous leaves. Evergreen , usually broadest in the middle . Alternate leaf arrangement . Leaf margin serrate from base to tip . Leaves mostly 1" to 2" long. • Fall foliage: Evergreen , so no fall color. Leaves also shiny in winter season .

Size/Age/Growth

Growth Rate: Slow to moderate. • Size: to 8' tall, but less than 12" wide.

Landscaping

Landscape Uses: As a formal accent or container specimen. As a foundation plant. In mass planting . Useful for high quality evergreen foliage . For formal gardens with sheared plantings. • Liabilities: Lack of all around cold hardiness in any location in zone 5. Foliar burn , twig kill in severe winters. Spider mite can be problematic in planting incorrectly sited in hot, dry. locations. Thielaviopsis blight can cause twig death on stressed plants . Somewhat overused in some neighborhoods or regions. Iron chlorosis on high pH soils. • Care: Follow a regular watering schedule during the first growing season to establish a deep, extensive root system . Feed with a general purpose fertilizer before new growth begins in spring . For a tidy, neat appearance , shear annually to shape .

Biology

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Growth

Culture: Needs protection from drying winter winds. Full sun to partial shade. Easily transplanted from container or B&B. Withstand significant pruning or shearing. Moist, slightly acid soils , well-drained soils are ideal. Tolerant of conditions in urban gardens. Plant 6 feet apart in mass plantings . Plant 3 feet apart in hedges .

Soil: Requires well-drained, slightly acid, fertile soil. • Minimum pH: 6.1 • Maximum pH: 6.5

Sunlight: Sun Exposure: Full to partial sun

Moisture: Water Requirements: Water regularly, when top 3" of soil is dry.

Temperature: Heat Zones: High: 7 (>60 to 90 days) Low:4 (>14 to 30 days) (map) • Cold Hardiness: 6a, 6b, 7a, 7b. (map)

Taxonomy

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Domain: Eukaryota () - Whittaker & Margulis,1978 - eukaryotes
- Kingdom: Plantae () - Haeckel, 1866 - Plants
  - Subkingdom: Viridaeplantae () - Cavalier-Smith, 1981
    - Phylum: Tracheophyta () - Sinnott, 1935 ex Cavalier-Smith, 1998 - Vascular Plants
      - Subphylum: Euphyllophytina ()
        Infraphylum: Radiatopses () - Kenrick & Crane, 1997
        Class: Spermatopsida () - Brongniart, 1843
        Subclass: Asteridae () - Takhtajan, 1967
        Superorder: Celastranae () - Takhtajan, 1967
        Order: Aquifoliales () - Senft, 1856
        Family: Aquifoliaceae () - Bercht. & J. Presl, 1825, nom. cons.
        Genus: Ilex () - C. Linnaeus, 1753 - Holly
        Specific epithet: crenata
        Cultivar: Sky Pencil
        Botanical name: - Ilex crenata 'Sky Pencil'

Notes

Listed as 'Sky Sentry' in Canada.

An accepted name in the RHS Horticultural Database.

Similar Species

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Members of the genus Ilex

ZipcodeZoo has pages for 299 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them:

More Info

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Notes

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Contributors

Brands, S.J. (comp.) 1989-present. The Taxonomicon. Universal Taxonomic Services, Zwaag, The Netherlands. Accessed May 2, 2012.

Identifiers

Zipcode Zoo Species Identifier: 709964

Footnotes

"Ilex". in Flora of Pakistan Page 1. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org. [back]

Ilex crenata 'Sky Pencil'

Overview

Interesting Facts

Common Names

Description

Genus Ilex

Physical Description

Size/Age/Growth

Landscaping

Biology

Growth

Taxonomy

Notes

Similar Species

Members of the genus Ilex

More Info

Further Reading

Notes

Contributors

Identifiers

Footnotes