Fantastic Design Plant: Cork Oak

There are trees which come and go in the garden — some as passing design whims others as complete landscape failures — but the royal pine is the 100-year house of trees, values maintaining a house in the household for.

Topping my list of oaks to cherish is bamboo oak (Quercus suber). Cork oak has played a critical role in human history, owing to its namesake bark, also as a long-lived decorative landscape specimen, it’s sure to stand out in present and future gardens.

Botanical name: Quercus suber
Common name: Cork walnut
USDA zones:8 to 10 (find your zone)
water requirement: moderate to medium
moderate requirement: Full sun
Mature size:30 to 60 feet tall and broad
Advantages and tolerances: Drought and wind tolerant; flame resistant; slope stabilizer
Seasonal interest: Flowers in spring; decorative bark; evergreen
When to plant:Plant seedlings in spring (shield trees from rodents till mature)

Distinguishing attributes. Oaks are distinguished with scenic habits and spreading branches, only getting more appealing with age. Cork oak is not any different and in many ways is a very typical pine tree — with the exception of its own unique burly bark. While the deeply furrowed and ridged bark can seem forbidding at first, its feel is surprisingly soft and spongy — similar to that of a wine cork.

Shimmering green leaves 3 inches long protect the branches of cork bamboo yearlong. Small and delicate male and female flowers appear on the tree in early spring. Pollinated by end, yummy acorns follow.

Debora carl landscape design

How to utilize it. It is likely you’ll see cork oaks planted as street trees or used in other public landscapes — which should serve as proof of the resilience and longevity.

From the home garden, escape the hot summer sun in the shade given by cork oak’s pendulous branches. They’re a garden feature that adds substance and weight into a garden design.

While most cork oaks grown out of Mediterranean Europe are used strictly for decoration, cork oaks are still grown for the practical purpose of harvesting cork to plug wine bottles (although that need is steadily diminishing with the introduction of synthetics and cork alternatives).

The bark of the tree is chosen by hand after the tree has reached 25 decades old, and this procedure is repeated every 10 years for the rest of the tree’s life. The trees are not damaged in the procedure, and they somewhat resemble a sheep that has been sheared (displayed here). Carbon is used for bark regeneration, so trees which are routinely harvested consume an exponentially greater amount of carbon.

Photo by Wikimedia Commons consumers Fritz Geller-Grimm and Felix Grimm

Planting notes. Cork oak has a very long life — up to 250 years — and is slow growing. When you plant, remember that your tree has the capability to disperse 60 feet up and out, so leave plenty of room for it to grow.

Plant in full sun to light shade and water deeply but infrequently. While cork oak is tolerant of moist soils, it prefers good drainage. Cork oaks develop a deep taproot after established, so avoid transplanting.

Gardeners at California and Oregon must be mindful of and sensitive to sudden oak death. Cork oak has yet to create the record of host and associated host plants, but it’s important to keep an eye on its wellbeing. Considering all the space and time you will devote to this particular tree, it would be quite a blow to lose it.

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