Species

Ilex crenataJapanese Holly

18 other cultivars

shrub

Japanese Holly

Ilex crenata 'Convexa'

The Story

Plant Bio

Ilex crenata, commonly known as Japanese holly, is a dense, multi-branched evergreen shrub native to East Asian forests and mountain slopes. It features small, spineless, glossy dark green leaves and inconspicuous white flowers in late spring that develop into black drupes on female plants.

'Convexa' is distinguished by its tiny, spoon-like leaves that are distinctively cupped upward, creating a highly textured, reflective surface. This cultivar grows twice as wide as it is tall, forming a broad, rounded mound that tolerates tight shearing and topiary.

Uses & Benefits:

Features unique, upward-curved glossy leaves and a dense, mounding habit that responds beautifully to formal shearing and topiary.

Serves as an excellent, low-maintenance boxwood alternative for formal hedges, foundation plantings, and structural garden borders.

Inconspicuous flowers attract general pollinators like bees, while the dense evergreen foliage provides nesting cover for birds.

SpeciesIlex crenataJapanese Holly

Essentials

At a Glance

Plant Type

Shrub

Height

96"

Width

192"

Light

Full Sun, Partial Sun

Zones

6, 7, 8

Water

Moderate

Humidity

Struggles in excessively hot, humid summers

Lifespan

Long-lived

Native To

Japan, Korea, China, and eastern Russia

Toxicity

Toxic to pets and humans if ingested

Bloom period

Late spring – Early summer

In flower about 2 months of the year

Planting

How to Grow

Select a site with full sun to partial shade and acidic, exceptionally well-drained soil.
Dig a hole twice as wide as the root ball but equal in depth, ensuring the crown sits slightly above the surrounding soil level.
Backfill with native soil, press firmly to eliminate air pockets, and water deeply to settle the roots.
Apply a two-inch layer of organic mulch around the base, keeping it clear of the main stems to prevent rot.
Water regularly during the first growing season to establish a deep root system, allowing the soil to dry slightly between waterings.

Pro Tip

Never shear back into the bare, leafless interior wood of the shrub, as it lacks the latent buds of boxwood and will not regenerate, leaving permanent bare patches. Ensure the planting site has excellent drainage, as heavy or waterlogged soil rapidly triggers Phytophthora root rot.

Keep It Thriving

Care Guide

Do

Prune regularly during the active growing season to maintain a neat, formal shape.
Plant in highly permeable, acidic soil to prevent root rot.
Apply a slow-release acidic fertilizer in early spring.
Monitor for spider mites and scale insects during hot, dry summer periods.

Don't

Do not cut back hard into old, leafless interior wood, as it will not regenerate.
Do not plant in heavy, poorly drained clay or low-lying areas where water collects.
Do not over-fertilize, which can stress the root system.
Do not allow the soil to dry out completely during prolonged heatwaves.

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Fertilize
Pest Check
Propagate
Prune

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Formal hedgesTopiaryFoundation plantingsMass plantingsSpecimen plant

Companion Plants

Rhododendron Pieris japonica Camellia

Multiply

Propagation Methods

Good to Know

Common Questions

Japanese Holly questions

What zones can Japanese Holly grow in?

Japanese Holly is hardy in USDA Zones 6–8. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Japanese Holly deer resistant?

Not reliably. Deer may browse Japanese Holly, especially tender spring growth — plan on repellents or fencing where pressure is high.

When does Japanese Holly bloom?

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

Does Japanese Holly need full sun?

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

Is Japanese Holly drought tolerant?

Yes — once established (usually after the first full season), Japanese Holly handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.