Holm Oak – Quercus Ilex

Holm Oak Quercus Ilex

Holm is another word for Holly and the Holm Oak is often called the Holly Oak as its leaves are very similar to those of a holly bush.


Holm Oak Tree General Information

The Holm Oak is a large evergreen, native to the Mediterranean region and is thought to have been first introduced into the UK in the 16th century.

This hardy tree has a beautiful rounded canopy and low hanging branches, with its shape and size giving a lovely architectural presence.

Added to this, its ability to tolerate shade and air pollution make it a very popular tree for public parks, city and suburban streets as well as gardens.

The Holm Oak is a slow growing tree prized for its very hard wood and has been used for making pillars, wagons, boats, tool handles and furniture.  Used as firewood the timber is often collected to make charcoal.

The Holm Oak can live for about 400 years and reach between 65 to 70 feet in height when mature.


Description of a Holm Oak Tree

The bark of a young tree is smooth and light green or grey in colour, darkening with age and becoming furrowed.

Leaves are a shiny dark green and leathery in texture, although the bottom of the leaves have very fine hair and are a silvery colour.

Resembling holly leaves and with prickly edges, as the tree mature these sharp points disappear as the leaf edges soften.

An evergreen tree, old leaves fall 1-2 years after the new leaves have emerged.

It also has a large spreading leafy canopy and a thick trunk.

The flowers are very small, elongated yellow catkins with both male and female flowers on the same tree.

Pollinated by wind, the female flowers develop into acorns.

These acorns are very similar to a standard acorn and sit within a scaly cup.

Green when young they turn a reddish brown when they mature and fall in the autumn.


Cultivation of a Sycamore Tree

Preferring a moist to dry soil of sand or clay the Holm Oak has the unique ability to be able to grow in full shade.

Although the Holm Oak can tolerate high winds and withstand maritime conditions, including salt air, it cannot survive in regions with freezing temperatures and fairs much better in the south of the UK.

Adding ornamental value to a variety of landscapes, the tree does best on seaside properties and makes an excellent windbreak.


Pests and Diseases

Due to being a hardy species it is not susceptible to many diseases and is generally disease free.

There are however a few problems such as root rot, which happens if the root system is made to stand in water for a long period of time.

The symptoms include fungus growing on the tree roots which can then spread to the trees bark and branches.

Wilt, which is a serious disease, affects the trees leaves, stunting foliage and turning it yellow.

Other symptoms include leaf curling and leaves dying and dropping prematurely.

A pest affecting this tree is the Holm Oak leaf mining moth, for which there is no control.

Fortunately, even when heavily infected by the pest, the Holm Oak withstands the damage caused and continues to grow.

Aphids can also be a problem with this particular tree.


Best Time for Pruning

Due to the Holm Oak being a rather dense tree regular thinning is recommended to increase air circulation and pruning will keep this tree a manageable size.


Article was written by Karen Arnold.

Edited by Conner D on 01/07/2019.

Article Source: https://www.graftingardeners.co.uk/holm-oak-quercus-ilex/

14 Responses

  1. How near to a permanent dwelling should a holm oak be? It is already at a height of 20feet plus and the Tarmac surround on the drive has cracked & is lifting making the ground hazardous. It also has a TPO.
    Thank you for any advice.

    1. Dear Christine Martin,

      It would be a good idea to have the tree about 20 to 25 feet from your home.

      Hope this helps.


      GraftinGardeners Team.

  2. Thank you for your very informative notes. Excellent!
    Is it possible to prune it annually from planting, to keep it as a very small tree, perhaps max. of 2.5 metres high and similar spread?
    We would LOVE to have one but can’t allow it to grow much bigger.
    Your advice would be GREATLY appreciated.

    1. Hi David,

      It would be possible to reduce the crown and trim the branches every year which would control the growth of the tree.

      Hope this helps.


      GraftinGardeners Team.

    1. Good Question Homayoon,

      Pollination will begin during May and the acorns will fall off around mid-September.

      This means it will take about three and a half months for the seeds to fall and it will also take another month for the tree to drop all of its acorns.

      Hope this helps.


      GraftinGardeners Team.

  3. Hi, is it possible to remove a holm oak tree which is around 9-10 feet tall ?

    its too close to the building and I fear will cause problems in the future

    1. Hi Puneet Mehta,

      It can depend on a few factors such as if the tree is subject to a TPO or you live in a tree conservation area. In this case you would need to obtain permission to remove or prune the tree.

      We can apply for permission at no cost if you are based in London and North Surrey.

      Hope this helps.


      GraftinGardeners Team.

      1. My neighbour has just planted a Holme Oak on our boundary line approx 6 ft from my house and 8 ft from my bock paved driveway. I expressed my concerns and he told me that he intends to keep it pruned at about 8-10 ft. He was also told by the nursery that the main root is a tap root so should it should not affect my house. Should I be concerned?

        1. Hi Susanna,

          As long as the it is kept at a reasonable height and it is regularly pruned it shouldn’t be much of a concern as it is a tap root which grows straight down.

          Obviously if it is left unmanaged it could cause problems later on down the line.

          Thanks for your comment.

          GraftinGardeners Team.

  4. Thank you for a great article.

    We’ve inherited a Holm Oak in the garden of our new home. It’s lost a large branch at some point as it has a large approx 2ft scar on the trunk about half way up the tree. (I’d estimate it to be about 30ft tall and potentially but no more than 40 years old).

    I have noticed that some of the lower branches are completely dead, some sections of leaves are completely dead on live branches and finally some of the younger twiggier growth coming out from the trunk also have only dead leaves. The top of the tree above the scar looks healthy and vigorous.

    Should we be concerned or is this natural for this tree? It isn’t in a problematic position, but we’d like to be able to help it rejuvenate or save it if it’s sick. In last year’s hot summer it has virtually no acorns, which I also thought was unusual.

    Many thanks in advance.

    1. Hi Old School Cat,

      Lower insignificant branches often die back, this is because it is a waste of energy for it grow branches (which hosts leaves obviously) where there is little light. Instead it will put its energy into growing towards the light.

      It is common for a holm oak to be quite “woody” internally. Most growth is on the outer 15 – 20% for the reason explained above.

      If you are concerned about either the aesthetics of the tree or safety (falling dead branches) you can call a local tree surgeon and ask them to deadwood the tree.

      I would recommend you one use a contractor found here: https://www.trees.org.uk/Find-a-professional this will mean the tree work is carried out in accordance with British Standards (BS3998)

      Holm oaks usually start fruiting (producing acorns) at 20 years, but that depends on environmental factors. They are most productive at around the 100-year mark. Throughout a really hot summer it does have an impact on all trees, although holm oak which is native to the Iberian Peninsula should not be affected.

      Although this species of oak is very resistant to pests and diseases, it can still be affected by chronic oak decline and Acute oak decline. Again if you are concerned most Arboricultural companies offer a free no-obligation consultation and quotation.

      The time to inspect and deadwood the tree should take no more than half a day when carried out by a professional tree surgeon.

      Thanks for your comment.

      GraftinGardeners Team.

  5. Thank you for your article, finding it very difficult to get anyone with knowledge about these trees in Southern Ireland.

    1 have 15 trees as screeening (2 metre standards planted 5 years ago, now about 5 metres tall), 2 trees have suffered badly from leaf dropping, going from dark green to light almost yellow green, thankfully one has fully recovered over 2 years and is now thriving, but the other tree has not grown at all this year, and it is not looking good. Appreicate any ideas as to a specialist I could engage with on this matter ..remotely if required..

  6. Would it be possible to grow and keep a Holm Oak in a tub? If so, what sort of size pot would be ideal as a permanent home?

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