Holly (Ilex 'Centennial Girl')

Overview

Ilex ‘Centennial Girl’ is a distinguished broadleaf evergreen Holly, highly sought after for its vibrant winter display. This female clone produces an abundant crop of rounded, bright red berries following inconspicuous greenish-white flowers in May. Its dense, pyramidal habit makes the Ilex ‘Centennial Girl’ an excellent structural plant for year-round visual interest in the landscape.

As a cross between Ilex centrochinensis and Ilex aquifolium, this Holly cultivar offers improved hardiness over some traditional holiday favorites, thriving in USDA Zones 5 through 9. Gardeners value the contrasting matte green foliage against the persistent red fruit, providing essential color when other plants are dormant. Proper siting and pollination are key to maximizing the ornamental impact of this reliable specimen.

Though requiring medium maintenance, the reward for planting the Ilex ‘Centennial Girl’ is a substantial evergreen screen or specimen that matures between 12 to 15 feet tall. Its ability to withstand urban conditions, including modest air pollution tolerance, adds to its versatility in many different garden settings.

Fast Facts

Plant Family: Aquifoliaceae
Plant Type: Broadleaf evergreen
Hardiness Zones: USDA Zones 5-9
Size at Maturity:
- Height: 12-15 ft
- Spread: 5-8 ft
Bloom Time: May
Bloom Description: Greenish-white
Sun Exposure: Full sun to part shade
Water Needs: Medium
Maintenance Level: Medium

How to Grow

Planting the Ilex ‘Centennial Girl’ is best done in spring or fall to allow root establishment before extreme weather. Choose a location that provides average, moist, slightly acidic, and well-drained soil. While this Holly handles full sun well, afternoon shade is highly recommended in hotter regions to prevent potential leaf scorch. Ensure the northern plantings are sited in sheltered areas, protected from harsh winter winds, to safeguard its superior hardiness in Zone 5.

Water needs are medium; maintain consistent moisture, especially during the first few growing seasons, ensuring the soil never completely dries out, nor becomes waterlogged. Fertilize sparingly, focusing on balanced, slow-release formulations if needed, particularly when addressing chlorosis, which may signal high pH issues in the soil.

Pruning should focus mainly on shaping or removal of dead wood, as the natural pyramidal form of the Ilex ‘Centennial Girl’ is highly attractive. Remember that this is a female clone; without a suitable male pollinator (like a male blue holly) nearby, you will not achieve the signature abundant crop of bright red fruit.

Landscape Uses

The robust, upright structure of the Ilex ‘Centennial Girl’ makes it an outstanding choice for creating dense, formal hedges or effective sight screens throughout the year. Its height potential of up to 15 feet allows it to quickly establish privacy barriers where a solid, substantial evergreen presence is needed. It also performs admirably when incorporated near foundations where its structure can anchor the architecture.

For borders, consider pairing the Holly with deciduous shrubs or late-blooming perennials that provide textural contrast in summer and autumn. The bright red berries offer spectacular contrast against plantings with white or pale yellow winter interest, such as Cornus alba ‘Elegantissima’ or certain yellow-twig dogwoods.

Standout Features

Flower Qualities

Insignificant

Fruit Qualities

Showy

Noteworthy Characteristics

Ilex is a genus of over 400 species of evergreen and deciduous trees, shrubs and climbers from tropical, subtropical and temperate regions. Many are grown for their attractive, evergreen foliage.Genus name comes from the Latin name Quercus ilex for holm oak in reference to the foliage similarities (holm oak and many of the shrubs in the genus Ilex have evergreen leaves). ‘Centennial Girl’ is a pyramidal, female, evergreen holly with matte green evergreen foliage and an abundant supply of bright red fruits that ripen in fall and persist throughout winter. It typically matures to 12-15’ tall and to 5-8’ wide. It is the result of a cross between Ilex centrochinensis and Ilex aquifolium. ‘Centennial Girl’ features spiny, ovate to oblong-elliptic leaves (to 2” long and 1” wide) with satiny surfaces, sinuate margins, acuminate apexes and cuneate bases. Nine to 14 spines per leaf. Greenish-white flowers (in small clusters) appear in May and are generally inconspicuous. Pollinated flowers give way to an often abundant crop of rounded berries (each to 1/3”) which mature to bright red in fall and remain on the plant throughout winter. ‘Centennial Girl’ has better winter hardiness (USDA Zone 5) than parent Ilex aquifolium (USDA Zone 7). U.S. Plant Patent PP10,750 was issued on January 12, 1999.

Tolerances

Air Pollution

Potential Problems

Be vigilant for several common pest issues, including scale insects, whiteflies, spider mites, and the holly leaf miner, which tunnels beneath the leaf surface. Treat established infestations promptly using horticultural oils or systemic insecticides appropriate for the pest in question.

Fungal diseases like leaf spot, tar spot, and powdery mildew can occur, especially in areas with poor air circulation or high humidity. Ensure adequate spacing between shrubs and incorporate good cultural practices, such as watering the base of the plant rather than the foliage.

Monitor for non-pest stress symptoms: leaf scorch from intense sun or dry winds, leaf drop from transplant shock or improper watering, and chlorosis (yellowing) if the soil pH is too high, inhibiting nutrient uptake.

Frequently Asked Questions

What hardiness zones is Holly suitable for?

Ilex ‘Centennial Girl’ performs best when situated in the ground within USDA Hardiness Zones 5 through 9.

How large does Ilex ‘Centennial Girl’ grow?

This evergreen Holly is moderately sized, generally reaching a mature height between 12 to 15 feet tall, with a spread of 5 to 8 feet wide.

What sun exposure does Holly need?

For optimal growth and fruiting, plant Ilex ‘Centennial Girl’ where it receives full sun to light part shade. Avoid harsh afternoon sun exposure in the hottest parts of the summer.

When does Ilex ‘Centennial Girl’ bloom?

The inconspicuous flowering period for this variety occurs in May, producing tiny greenish-white blossoms that may lead to an abundant crop of red berries if pollinated.

Conclusion

The Ilex ‘Centennial Girl’ offers exceptional year-round structure and brilliant winter color, making it a cornerstone plant for any four-season landscape design. Ensuring adequate pollination is the key horticultural task for maximizing the showy red fruit display of this Holly. Before planting, confirm your location falls within Zones 5-9 and prepare the soil to be slightly acidic and well-drained for success with this superb cultivar.

Design Ideas

When using the Ilex ‘Centennial Girl’ for screening, consider staggering the plants slightly rather than planting in a perfectly straight line. This informal layering technique helps break up the visual mass and allows better air circulation between individual shrubs, which aids in disease prevention. The resulting hedge will appear fuller and more naturalistic while still providing substantial privacy screening.

For foundation planting, select specimens that are slightly smaller or utilize annual pruning to keep the bottom branches neatly trimmed away from the structure. Place shorter, contrasting evergreen groundcovers, such as creeping juniper or low-mounding sedums, at the base to highlight the upright, spiny foliage of the Holly.

Companion Planting

Excellent companions for Ilex ‘Centennial Girl’ should share its preference for medium water and slightly acidic soil, while offering complementary flower or foliage color. Consider planting late-flowering hydrangea varieties that bloom once the Holly’s inconspicuous flowers have faded. Additionally, spring-flowering bulbs like daffodils or tulips planted beneath the canopy provide a lively show before the Holly’s foliage fully dominates the view.