Oak, Holly Quercus ilex
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Hardiness Zones 7 - 11The Holly Oak can be expected to grow in the zones shown in color in the arborday.org zone map. View Map
Type of treeEvergreens
Mature HeightThe Holly Oak grows to be 40' - 70' feet in height.
Mature SpreadThe Holly Oak has a spread of about 50' - 60' at full maturity.
SunThis oak does well in full sun.
The holly oak tolerates a wide range of soil textures from acidic to slightly alkaline, salt, and drought.
ShapeThis oak has rounded shape.
The Holly Oak is a long lived, durable tree that will thrive in almost any location once established and stands up well to strong winds. It provides shade for large areas of the landscape.
The holly oak is a tough evergreen tree as wide as it is tall with a dense rounded crown. It has smooth gray bark. The leaves are a leathery, glossy, dark green and vary in size and shape. The margins may or may not be irregularly toothed. Acorns are produced in the firat year falling in autumn. Holly oak tolerates a wide variety of soil textures, salt, and drought, but is sensitive to cold. It requires regular watering until it is established and then should not be overwatered as this invites powdery mildew. Be sure to keep irrigation away from the base of the trunk as root rot can set in. It may require pruning when young to develop a strong branch structure. If left unpruned it can develop multiple leaders and take on a large shrub form. When given adequate soil space, it does well along streets and parking lots, and in parks and gardens in the western United States.
Birds and squirrels are attracted to the holly oak for food and shelter.
Holly oak is native to the Mediterranean region. The range is from Spain along the Mediterranean fringe east towards western Pakistan. Other common names are Holm oak and Evergreen oak. In the foothills of the Spanish Pyrenees, black truffles are grown on the roots of these trees.
The Holly Oak thrives in moist, well-drained soil, but can tolerate drought when established.
The leaves are alternate, simple, 1"-3" long, spine-tipped teeth or untoothed along the margin, leathery, glossy dark green above, gray-green and downy below. They have a stiff, holly-like texture.
Male flowers are drooping catkins, female are inconspicious.
In spring.with the new leaves
The Holly Oak produces elongated acorns 1" long, green-yellow and brown. Acorns mature in the first year.
Rate of growth refers to the vertical increase in growth unless specified differently. Rate, as is true for size, is influenced by numerous variables such as soil, drainage, water, fertility, light, exposure, ad infinitum. The designation slow means the plant grows 12” or less per year; medium refers to 13 to 24” of growth per year; and fast to 25” or greater.Manual of Woody Landscape Plants, by Michael Dirr.