Quercus ilex (Holm oak)

Botanical name

Quercus ilex

Other names

Holm oak, Evergreen oak, Holly-leaved oak, Holly-oak, Ilex

Genus

Quercus Quercus

Species

Q. ilex - Q. ilex is a large evergreen tree forming a dense crown of rounded leaves and inconspicuous yellow-green catkins in spring followed by characteristic acorns.

Foliage

Evergreen

Tree shape

Large, rounded crown

Awards

RHS AGM (Award of Garden Merit)

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Colour

Flower

Yellow-green in Spring

Foliage

Dark-green in All seasons

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How to care

Watch out for

Specific pests

Leaf mining moths , Aphids

Diseases

Generally disease-free.

Specific diseases

Oak galls , Oak wilt

General care

Pruning

Can be used as hedging in coastal areas if pruned accordingly.

Propagation methods

Grafting, Seed

Defra's Risk register #1

Plant name

Quercus ilex (Holm oak)

Common pest name

Oak jewel beetle; Oak splendour beetle; Two -spot woodborer

Scientific pest name

Agrilus biguttatus

Type

Insect

Current status in UK

Present (Limited)

Likelihood to spread in UK (1 is very low - 5 is very high)

3

Impact (1 is very low - 5 is very high)

5

General biosecurity comments

Native beetle attracted to stressed trees and which is one of the biotic factors contributing to Acute oak decline. Good silviculture practice can help to mitigate the decline in tree health.

Defra's Risk register #2

Plant name

Quercus ilex (Holm oak)

Common pest name

Scientific pest name

Acute Oak Decline

Type

Other

Current status in UK

Present (Limited)

Likelihood to spread in UK (1 is very low - 5 is very high)

3

Impact (1 is very low - 5 is very high)

5

General biosecurity comments

Serious disorder of oaks likely to be caused by a complex of organisms. Eradication is not feasible; but good silvicultural practices could help to reduce spread and impacts.

Defra's Risk register #3

Plant name

Quercus ilex (Holm oak)

Common pest name

Ramorum leaf blight; Ramorum shoot dieback; Rhododendron twig blight; Sudden oak death

Scientific pest name

Phytophthora ramorum

Type

Oomycete

Current status in UK

Present (Limited)

Likelihood to spread in UK (1 is very low - 5 is very high)

4

Impact (1 is very low - 5 is very high)

4

General biosecurity comments

Pathogen of larch and other hosts subject to EU emergency legislation. A containment strategy is in place in the UK; reflecting its presence in wider environment/forestry settings in some areas. EU regulatory status is under review.

About this section

Our plants are under greater threat than ever before. There is increasing movement of plants and other material traded from an increasing variety of sources. This increases the chances of exotic pests arriving with imported goods and travellers, as well as by natural means. Shoot is working with Defra to help members to do their part in preventing the introduction and spread of invasive risks.

Traveling or importing plants? Please read "Don't risk it" advice here

Suspected outbreak? Click here for contact details to report to the relevant authority.

Date updated: 7^th March 2019 For more information visit: https://planthealthportal.defra.gov.uk/

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Monthly care advice

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Where to grow

Quercus ilex (Holm oak) will reach a height of 15m and a spread of 12m after 20-50 years.

Suggested uses

Architectural, Coastal, Drought Tolerant, Low Maintenance, Mediterranean

Cultivation

Plant in deep, fertile, well-drained soil.

Soil type

Chalky, Clay, Loamy, Sandy (will tolerate most soil types)

Soil drainage

Moist but well-drained, Well-drained

Soil pH

Acid, Alkaline, Neutral

Light

Partial Shade, Full Shade

Aspect

North, South, East, West

Exposure

Exposed, Sheltered

UK hardiness Note: We are working to update our ratings. Thanks for your patience.

Hardy (H4)

USDA zones

Zone 9, Zone 8, Zone 7, Zone 6