Tuesday, May 18, 2010

Gymnocladus - Coffee Tree

A small genus composed of only 2 species native to temperate climates. They are part of the much larger Legume family which includes the Acacia, Honeylocust, Mesquite, Beans, Peas among many other plants.

* photos taken on July 31 2011 in Hyde Park, NY

Gymnocladus chinensis ( Chinese Coffee Tree )

Very close to being extinct in it's native China this is one of the worlds rarest trees and is a close relative of the Kentucky Coffee Tree of North America. Most in the wild are growing in poor soil conditions in the most isolated places in the worlds most crowded countries and the eventual size is unknown. However due to vigor of the few trees that I have seen and lack of pest & diseases I would estimate these trees could reach a maximum size of 140 x 100 feet with a trunk diameter up to 6 feet ( same as their North American counterpart ). Some records include: fastest growth rate - 3 feet.
Its massive ferny, bipinnate leaves, up to 45 x 24 inches, include many tiny leaflets, up to 1.5 inches in length. There are few better trees for offering a truly tropical appearance in a temperate climate. The foliage on some trees in purplish during spring before turning to luxuriant mid-green.
The smooth bark is light gray.
Hardy at least north to zone 7, it could be hardy as far north as zone 4 as long as it's requirements of long hot humid summers are met. More testing of this outstanding landscape plant are needed to determine its full range. It is unlikely to thrive in western Europe where summers are cloudy and cool.

* photos taken @ U.S. National Arboretum, DC

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

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

* photos taken on October 17 2010 @ U.S. National Arboretum, D.C.

Gymnocladus dioica ( Kentucky Coffee Tree )

The Kentucky Coffee Tree is a native to central North America ( from southeast South Dakota to central Minnesota to southern Wisconsin to southern Michigan to Grand Bend, Ontario to Hamilton, Ontario to western New York State; south to Oklahoma to Tennessee...also found in eastern PA & Maryland ). It is endangered in Canada however can be locally common in the Lower Thames Valley near Chatham, Ontario as well as in the Canard River Conservation Area near Amherstburg. In the Windsor/Essex County, Ontario region; its actual original populations are unknown due to poor documentation but it was probably widespread and common from River Canard to Essex town and south to Lake Erie as well as locally north of Wheatley and around Wapole Island. It also occurred at Pelee Island where now extinct however still occurs at some of the other Lake Erie islands as well as on the Ohio shore where it was moderately common during presettlement times. The Kentucky Coffee Tree occurred sporadically at Detroit, Michigan during the presettlement era. Outside its native range, it is hardy anywhere from zones 2 - 8 and is used as a street and parking lot tree as far north as Ottawa and even further.
It is a handsome fast growing tree that looks like the Honey Locust on steroids. Its light gray bark is coarsely textured and combined with its thick branchlets, this tree has a striking winter appearance.
The Kentucky Coffee Tree usually reaches around 80 feet when mature but it can grow much more on ideal sites; to 140 x 100 feet in size with a trunk up to 6.4 feet in diameter. It grows fast ( usually 2 but very rarely to 5 feet per year ) to 60 x 33 feet with a trunk diameter of 0.5 feet in 20 years. 5 inch root cuttings have been known to reach up to 4 feet in height during the first year with ideal conditions. Very large trees have been noted in Essex County, Ontario; Lake County, Ohio and in Philadelphia and Maryland and many other places. They also grow large in harsher climates outside its native range ( 80 feet in Colorado, and 75 feet in Boise, Idaho ).
The huge bipinnate leaves reach up to 2 to 4 feet in length and are composed of up to 100 + leaflets, up to 5 x 3 ( usually about half that ) inches. The foliage in spring opens attractive pink-red, soon turning to deep green above, light green beneath. Fall color is variable in color and timing. Most trees that I've seen color an attractive bright yellow during mid-autumn though the leaflets drop off rather quickly with the leaf rachis(s) soon to follow...similar to the Black Walnut.
The greenish-white flower clusters reach up to 15 inches in length. They are borne during early summer and are followed by pods, up to 15 inches in length, ripening during autumn and lasting into winter.
The twigs are very thick with tiny buds
The bark is light gray and divided into long scaly ridges on older trees.
It is very salt, flood, drought and urban tolerant making it an excellent street tree however is most vigorous on deep, fertile soil where its deep wide roots can roam in search of nutrients and water. Easy to grow, the Kentucky Coffee Tree is virtually immune to insect pests and disease. It should be pruned in September since it can bleed if pruned during late winter or spring.
For new plants - soak seeds in sulfuric acic for 4 hours and wash under cold water for 15 minutes then sow 1 inch or less deep. No scarification needed - or if can be soaked for 24 hours in water then soaked in sulfuric acid for 2 hours then filed. Germination these ways is usually within 2 weeks; naturally it can take up to 8 years. The seed can be sown on permanent site to avoid transplant shock. The majority of remaining Kentucky Coffee Trees in Canada where considered endangered are within the Canard River Valley floodplain forests south of Windsor or on the Lake Erie Islands. It is assumed that many of those trees ended up where they are from seed which travelled by water.
Pieces of roots 4 to 5 inches long can also be placed in prepared beds and kept moist and will develop in first year into sizable plants up to 4 feet tall.
The seeds were used by earlier settlers as a substitute for coffee. The Natives ate and cooked the seeds.
The Kentucky Coffee Tree has strong durable wood used for furniture, window sills and posts.

* photos taken @ Tyler Arboretum, Philly, PA

* photo taken in Howard County, Maryland

* photo taken Feb 2009 @ U.S. National Arboretum

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

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

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

* photo taken on June 6 in Baltimore Co., MD

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

* photo taken on Feb 2011 on Liberty Road, Baltimore, MD

* photo of unknown internet source

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

* photo taken on Oct 23 2012 in Harford Co., MD

* photo taken on Sep 30 2014 in Howard Co., MD

* photos taken on Oct 21 2014 @ U.S. Botanical Gardens, Washington, DC

* photo taken on Apr 16 2016 @ U.S. National Arboretum, DC

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

* historical archive photos

* photos taken on Nov 28 2015 in Dauphin, PA

* photo taken on July 17 2016 in Grand Bend, Ontario

* Kentucky Coffee Tree in Simcoe, ON

* Kentucky Coffee Tree in Delhi, ON

* Kentucky Coffee Tree in Amherstburg, ON

* Kentucky Coffee Tree in Port Dover, ON

* Kentucky Coffee Tree in Stratford, ON

* Kentucky Coffee Tree in Mitchells Bay, ON

* photos taken on Aug 24 2018 in Washington, D.C.

'Prairie Titan'
A male form with a handsome upright habit and great architectural appeal in winter. It is fast growing to 30 x 16 feet in 10 years. The blue green foliage often turns intense golden yellow in the fall. Hardy zones 3 to 8

* photo taken on Jul 19 2017 @ Rideau Hall, Ottawa, ON

has variegated cream foliage

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


  1. I have a Kentucky Coffee Tree in Steep Rock, Manitoba (zone 3a) which has survived the last two winters.

  2. It is hardy as far north as Manitoba and Saskatchewan, Canada....There is a small but thriving one in a botanical garden in Saskatoon, SK and a good sized one growing in Portage la Prairie, Manitoba this is also thriving.