Japanese holly
ilex crenata
Also known as: ["Box-leaved holly","Japanese holly"]
Overview
A slow-growing, evergreen shrub with small, dark green leaves and black berries, often used as a hedge or topiary.
Benefits & Perks
["disease resistant","deer resistant","cold hardy","aesthetic foliage","wildlife attractant (bees, butterflies, birds)"]
Botanical Classification
| Phylum: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Aquifoliales |
| Family: | Aquifoliaceae |
| Genus: | Ilex |
| Botanical Name: | Ilex crenata |
Plant Characteristics
Basic Information
- Category: Shrubs
- Suitable Location: outdoor garden bed or container in a sheltered spot
- Suitable For:
- Is Weed: No
- Allergenicity: low
Environmental Needs
- Climate: {"temperatureRange":"–15–35°C"}
- Hardiness: {"zones":"5–8"}
- Misting: rarely required, but beneficial during dry periods
- Drainage: Moderate to fast-draining; avoid waterlogged conditions.
- Soil Type: Well-draining, loamy soil with organic matter; can adapt to various soil types.
Maintenance Level
- Maintenance Level: moderate
- Toughness Level: moderate
- Pruning Frequency: Annually in late winter or early spring; light pruning can be done anytime to remove damaged growth.
- Pruning Intensity: Moderate; can tolerate heavy pruning but may take longer to recover.
Care Details
Ideal Sunlight Coverage:
Full sun to partial shade (4–6 hours of direct sunlight daily); tolerates shade but may become leggy in deep shade.
Sunlight Tolerance Tips:
Acclimate plants gradually to direct sunlight to avoid scorching; protect from intense midday sun in hot climates; adjust placement based on seasonal light changes.
Care Requirements
Care Difficulty
moderatemoderate
Sunlight
partial shade to full sun
Morning sun is ideal; provide afternoon shade in hot regions; rotate plant for even growth.
Watering
every 7–10 days, allowing soil to dry slightly between waterings
Water thoroughly until it drains from the bottom; allow soil to dry slightly between waterings; avoid overwatering.
Soil
well-drained, loamy soil with moderate organic content
pH: Acidic to neutral (pH 5.5–7.0).
Ensure good drainage; amend with organic matter; test pH periodically; avoid compacted soil.
Temperature
Hardy in USDA zones 5–8; tolerates temperatures from -20°F to 90°F; prefers cool winters and moderate summers.
Protect from frost in winter; avoid placing near heat sources in summer; maintain consistent temperatures for best growth.
Fertilizing
every 4–6 weeks during spring and summer, with a balanced slow-release fertilizer
Fertilize in spring before new growth; avoid over-fertilizing to prevent root burn; flush soil occasionally to remove salt buildup.
Propagation
Methods
Stem cuttings or layering; semi-hardwood cuttings root most reliably.
Step-by-Step Propagation Guide
- Take 4–6 inch cuttings.
- Remove lower leaves.
- Dip in rooting hormone.
- Plant in medium.
- Maintain humidity with a plastic cover.
Best Time: Late spring to early summer when new growth is mature but not woody.
Environment
High humidity (70–90%), warm temperatures (65–75°F), and indirect light.
Medium
Peat-based mix with perlite or sand for good drainage.
Hormone
Rooting hormone is recommended to improve success rates.
Timeline
Roots develop in 4–8 weeks; new growth appears in 2–3 months.
Tools Needed
Pruning shears, rooting hormone, plastic bags or propagator, misting bottle.
Quick Tips
Use healthy, disease-free cuttings; keep soil consistently moist but not waterlogged; provide bottom heat if possible.
Pruning & Repotting
Pruning Guide
Method
Thinning cuts to open up the plant; heading cuts to encourage bushiness; selective removal of crossing branches.
Pruning Plan
Shape the plant, remove dead or diseased branches, and encourage dense growth; prune to maintain desired size and form.
Tools
Pruning shears, loppers, sharp knife, disinfectant.
Checklist
Disinfect tools; prune dead or diseased wood first; make clean cuts just above a bud or branch junction; remove no more than 1/3 of the plant at once.
Repotting Guide
Best Season
Early spring before new growth begins; avoid repotting during dormancy.
Pot Size
Increase pot size by 2–3 inches in diameter; ensure good drainage holes.
Method
Remove plant gently; trim roots if necessary; place in a slightly larger pot with fresh soil; water thoroughly after repotting.
Suggestions
Repot every 2–3 years or when roots fill the container; beneficial for container-grown plants to refresh soil and provide space.
Checklist
Choose appropriate pot size; prepare fresh soil mix; trim roots if crowded; water well after repotting; place in shade for a few days.
Advanced Care Tips
Watering Mastery
Watering Checklist
Check soil moisture before watering; water deeply; ensure proper drainage; adjust frequency based on season.
How to Apply Water Properly
Water at the base of the plant, ensuring moisture reaches the root zone; water early in the morning to minimize evaporation; ensure excess water drains away to prevent waterlogging.
Watering Schedule Tips
Water deeply once the top inch of soil feels dry; reduce frequency in winter to prevent root rot.
Soil Improvement
Add compost or peat moss to improve structure; incorporate perlite or sand for drainage; ensure organic matter is well-decomposed.
Temperature Stress Management
Signs of Temperature Issues
Leaf scorch in excessive heat; leaf drop or browning in cold stress; stunted growth in temperature extremes.
Cold Stress
Leaves may turn brown or drop; branches can become brittle; growth may slow or stop in prolonged cold.
Solution: Mulch around the base to insulate roots; protect from harsh winds; move potted plants to a sheltered location if temperatures drop below -10°F.
Hot Stress
Wilting, leaf scorch, or premature leaf drop; reduced vigor and flowering in prolonged heat.
Solution: Provide shade during peak heat; increase watering frequency; mist foliage in the morning to cool the plant.
Fertilizing Guide
Fertilizing Checklist
Use balanced fertilizer; apply in spring; follow package instructions; avoid winter feeding.
Fertilizing Method
Use a balanced, slow-release fertilizer in early spring; apply a diluted liquid fertilizer monthly during growing season; reduce or stop fertilizing in fall and winter.
Common Problems & Solutions
Toxicity Warning
Cats
ToxicIlex crenata berries are also toxic to cats. Consumption can result in gastrointestinal issues and other symptoms. Cats should be prevented from accessing the plant to avoid accidental ingestion.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Dogs
ToxicThe berries of Ilex crenata are toxic to dogs. Ingestion can lead to gastrointestinal upset and other adverse effects. While severe poisoning is rare, it is important to prevent dogs from consuming the berries.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Humans
ToxicIlex crenata, commonly known as Japanese holly, contains compounds that can be toxic to humans when ingested. The berries are particularly problematic, containing substances that can cause gastrointestinal distress and other systemic effects. The toxicity is generally mild to moderate, but ingestion should be avoided.
⚠️ Symptoms:
🌿 Toxic Parts:
⚡ Toxic If:
if eaten
Frequently Asked Questions
Q: Is Ilex crenata toxic to pets?
A: It is mildly toxic to dogs and cats if ingested.
Q: How fast does Ilex crenata grow?
A: It is a slow-growing shrub, typically adding only a few inches per year.
Q: Can Ilex crenata be grown in containers?
A: Yes, it can be grown in containers but requires well-draining soil and regular pruning to maintain shape.
Quick Reference
| Family: | Aquifoliaceae |
| Care: | moderate |
| Light: | partial shade to full sun |
| Water: | every 7–10 days, allowing so |
Get Expert Care Tips
Download the Plantious app for personalized care reminders and plant identification!
Google Play App Store
