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Description

The Holly oak grows into a large evergreen tree with a dense canopy habit, 30-60 ft. tall and as wide. Leathery leaves are dull green above, white below, and have intermittent spines on the margins. Pointed acorns are round, 1 in. long with the base often covering half the nut. Young trees develop an upright habit for the first 15-20 years before broadening into a rounded shape as they mature.

Holly oak comes from the Mediterranean region of Europe, including the western Himalayas where heat, cold and seasonal drought are common. It is a highly adaptable species that has been widely planted across the Inland Empire along streets, in parks and in residential landscapes . It shows good tolerance to heat and aridity like our native oaks, but has a greater tolerance for summer irrigation. Many trees have been planted in lawns and gardens for deep summertime shade.

Water Needs

Holly oak performs best in gardens and landscapes when planted in well-drained soils and when it receives normal winter rainfall along with low amounts of irrigation during summer. The chart shown below provides a baseline guide to the monthly irrigation schedule and volume of supplemental water needed to maintain healthy growth throughout the average year. It should be noted there are several months marked by an asterisk (*) when winter rains can provide sufficient moisture and irrigation is not needed.

Irrigation Schedule and Graph

Low Water Use Plants

Irrigation Schedule 2

  Jan* Feb* Mar* Apr May Jun Jul Aug Sep Oct Nov* Dec*
Runs per Month 0x to 2x 0x to 2x 0x to 2x 1x to 2x 1x to 2x 1x to 2x 1x to 2x 1x to 2x 1x to 2x 1x to 2x 0x to 2x 0x to 2x
Inches per Run 1" 1" 1" 1" 1" 1" 1" 1" 1" 1" 1" 1"
 
Inches per Month 0" to 2" 0" to 2" 0" to 2" 1" to 2" 1" to 2" 1" to 2" 1" to 2" 1" to 2" 1" to 2" 1" to 2" 0" to 2" 0" to 2"

Range of supplemental summer water: 7"-14"
Range of supplemental winter water: 0"-10"

 
0"-2"
0"-2"
0"-2"
1"-2"
1"-2"
1"-2"
1"-2"
1"-2"
1"-2"
1"-2"
0"-2"
0"-2"
  Jan* Feb* Mar* Apr May Jun Jul Aug Sep Oct Nov* Dec*
For more information on how to use this Irrigation Schedule and Graph, follow this link.

For information how to calculate your irrigation system’s schedule and precipitation rate, please follow this link.

Plant Properties

Plant Type: Tree
Foliage Character: Evergreen
Habit: Upright, Multi-trunk, Low-branching, Dense
Growth Rate: Moderate
Height: 30 ft. - 60 ft.
Width: 30 ft. - 60 ft.
Water Needs: Low 2
Foliage Color: Medium green
Flower Color: Insignificant
Flower Season: Spring
Soil Adaptations: Well-draining soil, Rocky soil, Deep soil, Calcareous soil, Acidic soil
Exposure Adaptations: Heat, Frost, Drought, Aridity, All day sun
Function: Wildlife value, Specimen, Shade Tree, Screening, Residential spaces, Parks and open space, Foliage accent plant, Commercial spaces, Civic spaces, Background plant, Attracts butterflies

Maintenance

Plan on light pruning when young to establish good long term structure. Prune lightly and remove dead wood in early fall as needed (D).

References

Associations

Plant Lists