Garden hybrid

This is a garden hybrid, bred from more than one wild species, so it has no single species page of its own.

2 other cultivars

shrub

Castle Spire Blue Holly

Ilex x hybrida 'Conty'

The Story

Plant Bio

Blue hollies (Ilex x meserveae) are dense, broadleaf evergreen shrubs known for their spiny, glossy, blue-green leaves and bright red berries on female plants. They are valued for their winter interest and hardiness.

CASTLE SPIRE ('Conty') is a female cultivar noted for its tight, narrow, pyramidal form, making it excellent for hedges or tight spaces. It produces an abundance of large, bright red berries when pollinated.

Uses & Benefits:

Provides strong, year-round architectural structure with its dense, evergreen foliage. In winter, it becomes a standout specimen, decorated with brilliant red berries against the glossy, blue-green leaves.

Its tight, upright, pyramidal form makes it an outstanding choice for creating dense privacy screens and formal hedges, especially in narrow spaces where a wider shrub would not fit.

The berries, which persist through winter, provide a vital food source for birds like robins, mockingbirds, and cedar waxwings when other food is scarce. The dense branches also offer shelter.

Garden hybrid

Bred from more than one wild species, so it has no species page of its own.

Essentials

At a Glance

Plant Type

Shrub

Height

108 inches

Width

42 inches

Light

Full Sun, Partial Sun

Zones

5, 6, 7

Water

Medium

Humidity

Average

Lifespan

Long-lived shrub

Native To

Hybrid

Toxicity

Berries are mildly toxic to humans and pets if ingested in quantity.

Bloom period

Late spring

In flower about 1 month of the year

Planting

How to Grow

Choose a site with full sun to part shade and well-drained, acidic soil.
Dig a hole twice as wide as the root ball.
Plant a male pollinator (like 'Castle Wall') nearby for berries.
Set the plant at the same depth it was growing in the pot.
Backfill with soil, water thoroughly to remove air pockets.
Mulch around the base to conserve moisture and suppress weeds.

Pro Tip

For berry production, plant one male 'Castle Wall' holly for every 5-7 female 'Castle Spire' hollies within 50 feet.

Keep It Thriving

Care Guide

Do

Provide consistent moisture, especially during establishment and dry spells.
Prune in early spring to maintain its formal shape.
Ensure a male pollinator is present for berry production.
Protect from winter wind and sun in the coldest parts of its range.

Don't

Don't let the soil dry out completely.
Avoid planting in poorly drained or alkaline soils.
Don't perform heavy pruning in late summer or fall.
Don't forget the male pollinator if you want berries.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Fertilize
Plant
Prune

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Formal evergreen hedge for privacyVertical accent at house cornersFestive winter interest specimen

Companion Plants

Buxus Rhododendron Hydrangea Hosta Thuja

Multiply

Propagation Methods

Good to Know

Common Questions

Castle Spire Blue Holly questions

What zones can Castle Spire Blue Holly grow in?

Castle Spire Blue Holly is hardy in USDA Zones 5–7. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Castle Spire Blue Holly deer resistant?

Yes — Castle Spire Blue Holly is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.

When does Castle Spire Blue Holly bloom?

Castle Spire Blue Holly typically blooms in late spring through late spring. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Castle Spire Blue Holly need full sun?

Castle Spire Blue Holly does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.