Cork oak Quercus suber
Cork oak (Quercus suber) is an evergreen perennial tree in the Fagaceae family, native to Western Mediterranean (Portugal, Spain, Morocco, Italy). It grows 10–20 m (33–66 ft) tall and 10–18 m (33–59 ft) wide, wants full sun and low water, and is hardy to about -10 °C (14 °F). Space plants about 12 m (39 ft) apart.
Plan Cork oak in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Cork oak at a glance
| Type | Perennial tree, evergreen |
|---|---|
| Family | Fagaceae |
| Mature height | 10–20 m (33–66 ft) |
| Mature spread | 10–18 m (33–59 ft) |
| Spacing | 12 m (39 ft) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Low; drought tolerance high, waterlogging tolerance none |
| Soil pH | 4.5–7 |
| Cold hardiness | About -10 °C (14 °F) once established (roughly USDA zone 8) |
| Heat stress | Likely above about 44 °C (111 °F) |
| Flowering | from about April for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Moderate |
| Pollinator value | Low |
| Edible | Yes: acorns (leached) |
| Native to | Western Mediterranean (Portugal, Spain, Morocco, Italy) |
| Common in gardens of | 🇫🇷 France, 🇪🇸 Spain, 🇵🇹 Portugal |
Is Cork oak toxic?
- People: mildly toxic
- Cats: mildly toxic
- Dogs: moderately toxic
- Parts: acorns, leaves
Oak tannins upset the stomach; harmful to dogs and livestock in quantity.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Cork oak
No well-documented helpful pairing. Group it with plants that like full sun and low water.
See Cork oak in a botanical garden
It grows in these sample gardens, which you can walk through in 3D:
- UC Botanical Garden, Berkeley (1 plants)
- Gardens by the Bay (1 plants)
Questions about Cork oak
- How far apart should I plant Cork oak?
- About 12 m (39 ft) apart, centre to centre. A mature plant spreads 10–18 m (33–59 ft).
- Does Cork oak need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Cork oak need?
- Low water. Drought tolerance is high and waterlogging tolerance none.
- How cold-hardy is Cork oak?
- It tolerates about -10 °C (14 °F) once established, roughly USDA zone 8.
- When does Cork oak flower?
- From about April for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Cork oak poisonous to cats and dogs?
- For cats it is mildly toxic; for dogs moderately toxic; for people mildly toxic. Oak tannins upset the stomach; harmful to dogs and livestock in quantity.
- What grows well with Cork oak?
- There is no well-documented companion pairing for Cork oak. Group it with plants that like the same sun (full sun) and water (low).
Sources and evidence
Evidence grade B (B: extension service or peer-reviewed).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- RHS Plant Finder, Royal Horticultural Society
Notes and assumptions
- Thick, spongy, fire-resistant bark harvested for cork every 9–12 years without felling the tree.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Sweet chestnut Castanea sativa
- English oak Quercus robur
- Southern live oak Quercus virginiana
- European beech Fagus sylvatica
- Holm oak Quercus ilex
- Coast live oak Quercus agrifolia
- Northern red oak Quercus rubra
- White oak Quercus alba