Broadleaf Evergreen Trees
Quercus ilex
holly oak
Fagaceae
Mediterranean Basin — Portugal to Turkey, including North Africa
At a Glance
TypeTree
HabitUpright
FoliageEvergreen
Height40-70 feet (12-21 m)
Width40-70 feet (12-21 m)
Maturity20 years
Growing Zones
USDA Hardiness Zones
7 - 10Zone 7
Zone 8
Zone 9
Zone 10
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancehardy
Key Features
Deer Resistant
Drought Tolerant
Maintenancevery low
Overview
A large, dense, rounded to broadly spreading broadleaf evergreen tree reaching 40-70 feet (12-21 m) tall and 40-70 feet (12-21 m) wide at maturity in favorable conditions. In the Pacific Northwest, typically 30-50 feet (9-15 m). Growth rate is slow to moderate, adding 8-16 inches (20-40 cm) per year. Long-lived, with specimens exceeding 500 years documented in the Mediterranean. Leaves are alternate, variable in shape — elliptical to lance-shaped, 1-3 inches (2.5-8 cm) long and 0.5-1.5 inches (1.3-4 cm) wide. Upper surface is dark glossy green and leathery; the underside is densely covered with gray-white to buff tomentose (woolly) pubescence, creating a distinctive bicolor effect when foliage moves in wind. Leaf margins are variable: juvenile leaves and those on lower branches are often spiny and holly-like (hence the common name), while mature leaves on upper branches are typically entire (smooth-edged) or with few teeth. This dimorphism between juvenile and mature foliage on the same tree is characteristic. Flowers appear in April to May: male flowers in yellow-green pendulous catkins 2-3 inches (5-8 cm) long; female flowers inconspicuous. Fruit is an acorn approximately 0.5-0.75 inches (13-19 mm) long, enclosed one-third to one-half by a scaly cup, ripening in fall of the same year. Acorns were historically used for food and animal feed in Mediterranean cultures. Bark is dark gray-brown, finely fissured and scaly with age. Exceptionally drought-tolerant once established. Tolerates salt spray, wind, and urban pollution. Hardy to approximately 5-10°F (-15 to -12°C).
Native Range
Native to the Mediterranean Basin, from Portugal and Morocco east through southern Europe, North Africa, and Turkey to the eastern Mediterranean. One of the most characteristic and widespread evergreen trees of the Mediterranean region. Found in maquis shrubland, open forests, and coastal areas from sea level to approximately 4,500 feet (1,400 m).Suggested Uses
Commonly planted as a large specimen shade tree, avenue tree, or windbreak in Mediterranean and coastal gardens. The exceptional drought tolerance and salt resistance make it increasingly valuable for Pacific Northwest landscapes as summers become warmer and drier. Traditionally used for formal hedging, topiary, and pleached allees in European gardens. Suitable for large-scale urban plantings due to pollution tolerance. Not suitable for small residential gardens due to the eventual large size. Acorns provide food for wildlife including squirrels, jays, and woodpeckers.How to Identify
Appearance
Size & Dimensions
Height40' - 70'
Width/Spread40' - 70'
Reaches mature size in approximately 20 years
Colors
Flower Colors
yellow
Foliage Colors
dark green
gray
Bloom Information
Bloom Period
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Detailed Descriptions
Flower Description
Yellow-green (catkins)Foliage Description
Dark glossy green above; gray-white tomentose belowGrowing Conditions
Sun Requirements
Full Sun
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Soil Requirements
pH Range5.0 - 8.5(Neutral)
357912
Soil Types
loamclaysandchalkrocky
Drainage
well drained
Water & Climate
Water Needs
Low
Frost Tolerance
hardy
Time to Maturity
15-20 years
Drought Tolerance
Drought tolerant when established
Care & Maintenance
Care Guide
Plant in full sun in well-drained soil. Tolerates a very wide range of soil types and pH from 5.0 to 8.5, including alkaline and calcareous soils. Exceptionally drought-tolerant once established — one of the most drought-resistant broadleaf evergreen trees suitable for the Pacific Northwest. Water regularly during the first 2-3 growing seasons to establish a deep root system; established trees require no supplemental irrigation in the Pacific Northwest. Tolerates salt spray, wind, and urban pollution. In zones 7b-8a, site in a sheltered position for the first several years; established trees are hardier than young specimens. No serious pest or disease problems in the Pacific Northwest. Sudden oak death (Phytophthora ramorum) is a potential concern but is not commonly reported on Q. ilex in this region.Pruning
Prune in late winter to early spring to shape and remove dead or crossing branches. Responds well to hard pruning and can be trained as a formal hedge, topiary, or pleached allee — a traditional use in European gardens. For hedge use, shear 1-2 times per year in summer. When grown as a specimen tree, minimal pruning is needed beyond structural training when young. Remove lower branches gradually to raise the canopy for clearance. The slow growth rate means pruning is infrequent once the desired form is established.Pruning Schedule
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winterearly spring