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Cork oak or holm oak? How to tell them apart
Quercus suber · Quercus ilex
How to tell them apart – cork oak: thick, soft and spongy cork bark; holm oak: hard bark cracked into small blocks, without cork.
How do you recognise them?
- Cork oak
- Evergreen oak with thick, soft and spongy cork bark and a small, toothed leaf with a grey-felted underside.
- Compared with holm oak: thick, soft and spongy cork bark.
- Holm oak
- Evergreen oak with dark green, leathery leaves that are grey-felted underneath; on young trees often spiny-toothed like holly.
- Compared with cork oak: hard bark cracked into small blocks, without cork.
| Cork oak | Holm oak | |
|---|---|---|
| Leaves | Alternate, evergreen, 3–7 cm, oval, with small bristle-tipped teeth; dark green above, grey-felted below. | Alternate, evergreen, 3–7 cm, oval to lance-shaped, untoothed or (especially on young trees) with spiny teeth; dark green above, greyish-white felted below. They stay on the tree for 2–3 years. |
| Flowering | Yellow, hanging catkins in April–May (May). | Yellow, hanging catkins in May–June (May). |
| Fruit | Acorns 2–3 cm long in a cup with somewhat spreading scales. | Small, pointed acorns 2–3 cm long in a grey-felted cup; they ripen in their first year. |
| Bark | Very thick, pale grey, deeply furrowed, corky and springy: you can press your thumb into it. After the cork harvest the trunk is reddish-brown. | Dark grey to blackish, cracked into small square blocks. |
| Shape and height | Broadleaf tree, 8–15 m (in Belgium usually smaller) | Broadleaf tree, 10–20 m (in Belgium usually 5–15 m) |
| Site | Full sun, acid soil, dry | Sun or partial shade, any garden soil, dry |
| Native to Belgium | No, planted | No, planted |
| Good for bees, butterflies and birds | – | – |
| Poisonous to people and pets | Not known to be poisonous | Not known to be poisonous |
| Pruning months | May–July | May–August |
What does it mean for your garden?
- Holm oak grows 10–20 m (in Belgium usually 5–15 m) tall: too big for an ordinary garden, but fine in a large garden, a park or a meadow.
Read on
- Plant profile: Cork oak
- Plant profile: Holm oak
- Cork oak: when and how to prune
- Holm oak: when and how to prune
- Identification key
Also looks like
Identify by feature
This comparison is compiled from the Bladwijzer species pages.