Sunday, January 17, 2010



A genus of 10 species of moderately long-lived, deciduous trees native to temperate climate regions of eastern Asia.
They prefer a continental climate with hot summers and cold winters. They are tolerant of hot reflected sun though strong dry winds can damage the foliage. The Cork Trees thrive in full sun on any well drained soil including alkaline, dry and clay. Insect and disease problems do not normally occur.
Propagation is from cuttings or seed which germinates easily. These trees are easy to transplant and are very soil, pollution, lime and drought tolerant.
Though not considered invasive, Phellodendrons have naturalized at Arnold Arboretum in Boston, MA where seedlings very frequently come up.

* photos taken on Aug 15 2014 @ Druid Hill Park, Baltimore, MD

Phellodendron amurensis ( Amur Cork Tree )
A very fast growing large tree native to far eastern Russia and northern China. Some records include: fastest recorded growth rate - 7 feet; 5 years - 20 x 7 feet;
10 years - 33 x 21 feet; 20 years - 66 x 33 feet; largest on record - 170 x 100 feet with a trunk diameter of 6 feet ( China ). Some trees have already grown large in the U.S. ( 50 x 62 x 3 feet in Denver, CO; 62 feet in Baltimore, 70 x 70 feet in Connecticut & 70 x 80 feet in Philly ). It has reached 60 feet at Dominion Arboretum in Ottawa, Canada.
The pinnate leaves up to 20 inches in length are composed of 9 to 13 untoothed, pointed oblong leaflets up to 6 x 2 inches in size. The leathery foliage is glossy very glossy deep green above, blue-green beneath; turning to golden-yellow early during autumn.
The flowers are borne in conical clusters up to 3.5 inches in length in late spring. Male and female flowers are borne on separate plants.
The fruits are small berries up to 0.25 inches in width that are borne dense clusters that are green later turning to black.
Fruits persist into winter unless eaten by birds.
The stout twigs are brown and straight.
The yellow-gray, deeply furrowed corky bark is also an ornamental feature.
It is pollution, drought and salt resistant but needs full sun and rich well drained soil. It is not prone to pest and diseases making it an excellent low maintenance landscape tree. it is hardy from zones 2 to 7 and does best north of Virginia. It grows well even in extremely harsh climates such as Edmonton, Alberta, Saskatoon and Newfoundland.

* photos taken on April 11 2010 @ U.S. National Arboretum

* photos taken on April 18 2010 @ U.S. National Arboretum

* photos taken on May 16 2010 @ Cylburn Arboretum, Baltimore, MD

* photos taken on July 17 2010 @ Morris Arboretum, Philly, PA

* photos taken on August 3 2010 @ University of Guelph Arboretum, Ontario

* photos taken on August 4 2010 @ Birnam Woods, Arboretum, Stratford, Ontario

* photos taken on Oct 19 2013 in Columbia, MD

* photos taken @ Middle Patuxent, Clarksville, MD on Apr 24 2015

'His Majesty'
Fast growing and upright. A hybrid between Phellodendron amurense & P. sachalinense that originated at the University of Minnesota.
It is a male clone that does not produce fruit.
Hardy zones 3 to 7.

Vigorous male clone that bears no fruit. It has thick leathery leaflets and unusually corky bark.

Phellodendron chinense
Similar to Phellodendron amurense except it is native to mountains of central China and this one does NOT have corky bark typical of this genus. The bark is thin and gray-brown instead. Fast growing, it has been recorded to reach 55 feet with a trunk diameter of 2 feet in 26 years. Its maximum size is unknown but likely similar to that of Phellodendron amurense.
The leaves up to 15 inches in length are similar to Phellodendeon amurense except that the leaflets, up to 6 x 2 inches in size, are deep-green above and lighter and hairy beneath, turning to brilliant yellow in autumn
. The female trees bear small black berries in dense clusters in autumn that contrasts well with the autumn foliage.
The stems have a rusty felted somewhat felted coating when young however this soon wears away.
Hardy zones 4 to 9 preferring a sheltered sunny sites on well drained fertile soil.

* photos taken on April 27 2012 in Columbia, MD

Phellodendron japonicum ( Japanese Cork Tree )
A large tree native to Japan that is more suited for mild winter climates than the similar Phellodendron amurense. It is not damaged by late spring frosts in climates with mild winters. Some records include: largest on record - 72 feet; largest in U.S. - 50 x 75 feet with a trunk diameter of 3 feet @ Morris Arboretum in Philly, PA. It thrives at Dominion Arboretum in Ottawa, Canada but tends to be a smaller in size than P. amurensis having only reached 30 feet in height.
The leaves, up to 14 inches in length, are composed of 9 to 13 ovate leaflets, up to 4 inches in length.
Hardy zones 3 to 8.

Phellodendron lavallei ( Lavalle Cork Tree )
A very rare large tree reaching up to 75 feet that is native to central Japan. Some records include: largest on record - 100 x 81 feet with a trunk diameter of 3.5 feet; largest in Pennsylvania - 70 x 81 feet with a trunk diameter of 3.5 feet at Morris Arboretum, Philly.
The pinnate leaves, up to 20 inches in length are composed of 5 to 13 pointed leaflets up to 7 x 3 inches each.
The foliage is reddish in spring turning to medium green above and finely hairy beneath in summer then to yellow in autumn.
The orange-scented fragrant flowers are borne in early summer.
The young shoots are covered in a rusty coating. The very attractive bark is red-brown, corky and thick.
Hardy zones 4 to 9. It is reported to grow in Washington, D.C. just southeast of the Library of Congress.

* photo taken on Nov 6 2013 in Columbia, MD

* photo taken on Nov 6 2015 in Columbia, MD

* photo taken on Oct 21 2016 in Columbia, MD

Extremely bright yellow autumn color.

Phellodendron sachalinensis ( Sakhalin Cork Tree )
A spectacular, very fast growing, large spreading shade tree native to western China, Sakhalin Island and Korea. Some records include: 6 years - 12 feet; largest on record - 100 feet with a trunk diameter of 5.5 feet.
The pinnate leaves, up to 15 inches in length are composed of up to 11 leaflets up to 5 inches in length. The foliage is matt medium green turning to brilliant golden-yellow in autumn.
The bark is dark brown, thin and shallowly ridged very unlike that of Phellodendron amurense.
Hardy zones 3 to 7b

* photos taken on August 3 2010 @ University of Guelph Arboretum, Ontario

* Additional photos of Phellodendron taken on Oct 19 2015 in Howard Co., MD

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