Thursday, May 13, 2010

Cladrastis - Yellowwood

A family of trees named the "Yellowwood" after the yellow timber and yellow color dye yielded from this tree. It is also grown for its attractive foliage and wisteria like flowers. The Yellowwoods do not produce spines.
Not very tolerant of severe drought or floods; the Yellowwood grow well on most well drained soils in full sun. They do however grow fastest on acidic, light, fertile, well drained soils. The Yellowwoods are deep rooted enough to plant underneath. Nitrogen fertilizers are not required since the roots fix nitrogen which means they actually produce their own fertilizer as do alot of other Legumes such as Soybeans. Young trees should be pruned to avoid narrow crotches that can split in windstorms as the tree ages. When young; the tree can be pruned in fall to a single leader and feathered ( meaning spacing and shortening side limbs as well as gradually removing lower limbs for a tree that can eventually be walked under ).
The Yellowwood should not be pruned in late winter or spring when they can bleed profusely. The best time to plant a Cladrastis is in April shortly before the tree leafs out. Young trees with thin bark should have the trunks wrapped with appropriate wraps during winter to protect from sunscald on sites where this may be a problem. An easy to grow, low maintenance tree; the Yellowwoods are not generally bothered by insect pests or disease and are tolerant of pollution, salt and urban conditions.
Propagated from either seed or hardwood cuttings taken in winter. Root cuttings taken in late winter will also work.
While I have never been able to photograph the Asian Yellowwoods in full bloom ( never seem to time it right ) they are lust like the native one beautiful trees in all seasons as well as easy to grow. I rate ALL the Yellowwoods as a 10 / 10 on my recommendation scale.

Cladrastis kentuckea ( Kentucky Yellowwood )
Also called Cladrastis lutea. A fast growing, very attractive, round canopied legume tree native to rich woodlands in the eastern U.S. ( from eastern Oklahoma to central Ohio; south to central Arkansas to central Alabama ). The Yellowwood is very rare in the wild however makes an excellent shade tree and lawn tree and is planted within and far beyond its natural range.
It can reach 60 feet or more and sometimes much more. Some records include: fastest recorded growth rate - 8 feet ( more than double the average ); 20 years - 50 x 60 feet; 30 years - trunk diameter of 2 feet; largest ever recorded - 93 x 96 feet with trunk diameter of 8 feet, another tree of 70 x 138 feet was recorded in New Hampshire. One very large tree is reported to grow at Old Moon Nursery in Morrisville, Bucks Co., PA., another grows at Bartram's Gardens in Philly. The Kentucky Yellowwood grows with a deep root system and is long lived up to 220 years.
The pinnate leaves, up to 15 inches in length, are composed of 7 to 11 oval to broadly-elliptical, non-toothed leaflets, up to 4 x 3 ( rarely 8 x 4.4 ) inches in size. The smooth, deep green foliage, turns rich buttery yellow ( sometimes orange ) during fall.
The fragrant, white, early summer flowers, up to 1.5 inches in size, are produced in long, hanging racemes up to 20 x 6 inches in size.
The blooms are followed by flattened, narrow, long brown seed pods up to 4 x 1 inches in size.
The twigs are stout and zig-zagged.
The bark is silvery, smooth and beech-like. The wood is yellow in color and up to 40 pounds per square foot.
Hardy zones 3 to 8. While there have been reports of zone 2 hardiness, most climate zone 2 areas would not support growth of the Yellowwood which prefers warm to hot summers. Established trees are fully hardy in Ottawa, Ontario however it is recommend to shelter seedlings in a cool greenhouse for the first few winters.

* photo taken on April 11 2010 @ U.S. National Arboretum, DC

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

* photos taken on May 1 2010 @ U.S. National Arboretum, D.C.

* photo taken on May 8 2010 @ McCrillis Gardens, Bethesda, MD

* photos taken on 4th of July 2010 in Washington, D.C.

* photo taken on May 16 2011 in Washington, D.C.

* photos taken on Aug 25 2011 @ Scott Arboretum, Swarthmore College, PA

* photo taken on May 7 2012 in Columbia, MD
* photo taken on May 15 2013 in Ellicott City, MD

* photo taken on May 7 2014 @ London Town Gardens, Edgewater, MD

* photo taken on May 6 2015 in Ellicott City, MD

* photo taken by Milan Havlis, owner of central Europe's premier plant nursery

* historic archive photos

* photo taken on July 15 2016 in Goderich, ON

* photos taken on Nov 19 2016 @ London Town Gardens, Edgewater, MD

* photo taken on May 4 2017 in Columbia, MD

* photos taken on Jul 18 2017 @ Dominion Arboretum, Ottawa, ON

* photos taken on Jul 19 2017 @ Major's Hill Park, Ottawa, ON

* photo taken on Nov 9 2017 in Harford Co., MD

Pink flowers. Also called 'Perkin's Pink'.

* photo taken on June 30 2013 @ U.S. National Arboretum, DC

* photos taken by Milan Havlis, owner of central Europe's premier plant nursery

More vigorous with exceptionally large flowers.

Cladrastis platycarpa ( Japanese Yellowwood )
Also called Cladrastis sikokiana. A moderate growing, rounded, medium to large sized, deciduous tree that is a native to eastern China and Japan. Some records include: largest on record - 80 x 40 feet with a trunk diameter of 3 feet; fastest growth rate - 4 feet. One tree already grew to 70 feet tall and 3 feet in trunk diameter in England where it is not native. A large tree of 38 years in age and a trunk diameter of 2.2 feet grows at Longwood Garden near Philly, PA. Long lived, up to 130 years and more.
The leaves, up to 13 inches in length, are composed of 9 to 15 ovate leaflets, up to 5 x 2 inches in size. The foliage is bright green, turning to orange during autumn.
The white flowers, up to 0.5 inches across, are borne on panicles up to 10 inches in length, during early summer.
The smooth bark is gray.
Hardy zones 4 to 8 preferring full sun on moist, well drained soil. When young they should be limbed up and pruned to avoid narrow crotches which can split in storms. It also thrives in hot humid summers making it an excellent tree for the Mid Atlantic and Midwest.

* photo taken @ U.S. National Arboretum, D.C. on Feb 2009

* photo taken on May 8 2010 @ U.S. National Arboretum, D.C.

* photos taken on 4th of July 2010 @ U.S. National Arboretum, D.C.

* photos taken on June 23 2013 @ U.S. National Arboretum, Washington DC

* photos taken on Apr 17 2016 @ U.S. National Arboretum, DC

* photos taken on Aug 5 2017 @ Brookside Gardens, Wheaton, MD

* photos taken on Sep 3 2017 @ U.S. National Arboretum, D.C.

Cladrastis sinensis ( Chinese Yellowwood )
Native to China, this is a fast growing tree reaching up to 70 feet on average. Some records include: 3 years - 8 feet; 5 years - 10 x 10 feet; largest on record - 95 x 80 feet with a trunk diameter of 4.2 feet.
The leaves are composed of up to 17 leaflets up to 5 x 2 inches in size. The foliage is late to appear in spring.
The light pink flowers are borne in clusters up to 12 x 10 inches in size.
Hardy north to zone 4. It thrives in eastern North America, the Pacific Northwest as well as the British Isles.

* photo taken on Apr 24 2016 @ U.S. National Arboretum, DC

Cladrastis wilsonii ( Wilsons Yellowwood )
Native to central China; this is a small tree reaching a maximum size of 33 feet with a trunk diameter of 14 inches.
The leaves are composed of up to 9 ovate leaflets up to 3 inches in length. The foliage is glossy deep green above and gray-blue below.
The white flowers are borne on clusters up to 7 inches long. The shoots are red.
Hardy north to zone 6

1 comment:

  1. I planted a yellow wood in 2000. It was about 6 feet tall at the time. It is now twice that height and seems very healthy, but it has never bloomed. This spring and in 2009, the leaves froze and fell off and the tree put out a new set of leaves. Would the freeze prevent it from blooming? I live near Buffalo NY. Also the bark has split in several places. Is that normal? I would appreciate any feedback.