Quercus ilex

RHS Plant Profile

holm oak

Other common names

evergreen oak, holly oak, holly-leaved oak, ilex

Trees

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A large evergreen tree with black, finely cracked bark, developing a massive, rounded crown. Glossy dark green, ovate leaves, whitish beneath contrast with whitish young foliage and yellow catkins

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

Higher than 12 metres

Max Spread

wider than 8 metres

Size

Time to Maturity: 20–50 years
Max Spread: wider than 8 metres
Max Height: Higher than 12 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Moist but well–drained or Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: South–facing or North–facing or East–facing or West–facing
Exposure: Exposed or Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H4
Drought Resistance: Yes

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Fagaceae
Native to GB/Ireland: No
Foliage: Evergreen
Habit: Bushy
Potentially harmful: Pets (dogs): Harmful if eaten - for further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
Genus: Quercus can be deciduous or evergreen trees or shrubs, with entire, lobed or toothed leaves; flowers inconspicuous, followed by characteristic acorns; sometimes good autumn colour
Name Status: Correct
Plant Range: Mediterranean

How to Grow

Cultivation

An easy to grow evergreen tree that responds well to formative pruning and clipping. Can be used as hedging in coastal areas and is suitable for most sites except the coldest inland areas. Leaf fall can occur in summer

Propagation

Propagate by seed sown in a coldframe or seedbed as soon as ripe or by grafting in mid-autumn or late winter

Suggested planting locations and garden types

Coastal
Mediterranean climate plants
Hedging and screens

Pruning

Pruning group 1

Pests

May be susceptible to aphids and leaf-mining moths

Diseases

May be susceptible to powdery mildews and honey fungus