Pin oak is named for a characteristic where small, thin, dead branches stick out like pins from the main trunk. Pin oak is among the most widely planted native oaks in the urban landscape, the third most common street tree in New York City. It tolerates drought, poor soils and is easy to transplant.
It is popular because of an attractive shape and trunk. The green, glossy leaves show brilliant red to bronze fall color. In many cases the pin oak is planted on inappropriate sites.
Scientific name: Quercus palustris
Pronunciation: KWERK-us pal-US-triss
Common name(s): Pin Oak
USDA hardiness zones: USDA hardiness zones: 4 through 8A
Origin: native to North America
Uses: large parking lot islands; wide tree lawns; recommended for buffer strips around parking lots or for median strip plantings in the highway; tree has been successfully grown in urban areas where air pollution, poor drainage, compacted soil, and/or drought are common.
The lower branches on pin oak cultivars ‘Crown Right’ and ‘Sovereign’ do not grow down at a 45 degree angle as does the non-cultivar. This branch angle can make the tree unmanageable in close urban settings. These cultivars are thought to be better suited than the species as street and parking lot trees. However, graft incompatibility often leads to future trunk failure on these cultivars.
Height: 50 to 75 feet
Spread: 35 to 40 feet
Crown uniformity: symmetrical canopy with a regular (or smooth) outline, and individuals have more or less identical crown forms
Crown shape: pyramidal
Crown density: moderate
Growth rate: medium
Leaf arrangement: alternate
Leaf type: simple
Leaf margin: lobed; parted
Leaf shape: deltoid; oblong; obovate; ovate
Leaf venation: pinnate
Leaf type and persistence: deciduous
Leaf blade length: 4 to 8 inches; 2 to 4 inches
Leaf color: green
Fall color: copper; red
Fall characteristic: showy
Trunk and Branches:
Trunk/bark/branches: bark is thin and easily damaged from mechanical impact; droop as the tree grows and will require pruning for vehicular or pedestrian clearance beneath the canopy; should be grown with a single leader
Pruning requirement: needs little pruning to develop a strong structure
Breakage: susceptible to breakage either at the crotch due to poor collar formation or the wood itself is weak and tends to break
Current year twig color: brown; green
Current year twig thickness: thin
Lower branches on a pin oak will require removal when used as a street or parking lot tree as they tend to droop and hang on the tree. The persistent lower branches can be attractive on a roomy large open lawn because of its picturesque habit when open-grown. The trunk is typically straight up through the crown, only occasionally developing a double leader. Prune any double or multiple leaders out as soon as they are recognized with several prunings in the first 15 to 20 years after planting.
Light requirement: tree grows in full sun Soil tolerances: clay; loam; sand; acidic; extended flooding; well-drained
Drought tolerance: moderate
Aerosol salt tolerance: low
Soil salt tolerance: poor
Pin Oak develops nicely on moist, acid soils and is tolerant of compaction, wet soil and urban conditions. When grown on an acid soil, pin oak can be a handsome specimen tree. The lower branches tend to droop, middle branches are horizontal and branches in the upper part of the crown grow upright. The straight trunk and small, well-attached branches make Pin Oak an extremely safe tree to plant in urban areas.
It is extremely vigorous as far south as USDA hardiness zone 7b but may grow slowly in USDA hardiness zone 8a. It is very sensitive to soil pH above the high 6’s. It is water tolerant and is native to stream banks and flood plains. Pin Oak grows well in areas where water stands for several weeks at a time. One of the adaptive mechanisms of Pin Oak is a fibrous, shallow root system which allows it to tolerate flooded soil conditions. But as with any other tree, do not plant it in standing water or allow water to stand around the roots until the tree has become established in the landscape. Several years are needed after transplanting for the tree to develop this type of adaptive root system, and subjecting it to flooding too early could kill it. Plant trees in a slightly raised mound or bed if soil is poorly drained.