Quercus phellos - Willow Oak

The Quercus phellos, or willow oak, is a species native to North America that is characterised by significant growth, an elegant ovoid habit, and especially fine-textured foliage reminiscent of a willow. Its leaves, shiny green in summer, turn yellow, or even almost orange in autumn. They may remain evergreen through mild winters. This oak with willow-like features makes a beautiful shade tree that will adapt to any non-calcareous soil.

Quercus phellos is native to the United States, where it naturally grows in coastal plains and river valleys, mainly in the southeastern part of the country. It is commonly found in wet but well-drained areas such as swamps, riverbanks, and lowland forests. It thrives in locations at the interface between dry and wet environments, alongside Acer rubrum, Fraxinus pennsylvanica, and Gleditsia triacanthos. This species was introduced to Europe in the 18th century. Like all oaks, it belongs to the Fagaceae family.

The willow oak exhibits moderately fast growth, which can vary depending on the growing conditions. In our climates, it can reach a height of 15 to 20 m and a spread of 6 to 8 m. It develops a massive trunk and a crown that is initially pyramidal, becoming ovoid, closed, and dense over time. The bark is smooth and dark grey on young trees, becoming slightly rough with age and peeling off in small plates. The young olive-green shoots have a velvety pubescence, but quickly become glabrous and greenish-brown. The leaves are finely lanceolate to sometimes linear, measuring approximately 5 to 15 cm in length and 1 to 1.5 cm in width. Their upper surface is dark green in summer, while their lower surface is glaucous. The leaf margin is entire and slightly undulate. In autumn, they turn pale yellow, yellow, or even orange, depending on the soil and climate. Golden catkins appear in May. The acorns are small, almost spherical, measuring 1 to 1.5 cm in length. At most, one-third of the acorns are surrounded by a cupule. They mature in two years.

Quercus phellos combines the graceful foliage of a willow with the imposing character of an oak. It should be planted in an open position where it will be visible from a distance. It can be cultivated as an ornamental tree in parks and large gardens, where it will express its full potential as a shade tree or specimen. Quercus phellos tolerates urban conditions and is resistant to wind, heat, drought, and occasional flooding. This species is disease-free but does not grow well in chalky soils. To accompany it, consider choosing, for example, an American sweet gum (Liquidambar styraciflua) with spectacular autumn foliage, whorled holly (Ilex verticillata 'Maryland Beauty') with beautiful red berries in autumn and winter, and a shrub like Viburnum dentatum 'Blue Muffin' with white flowers in summer and blue-black berries in autumn.