Friday, December 9, 2011

Leadtree

Leucaena

A genus of 50 species of evergreen trees mostly native to the American tropics and the Pacific Islands.
All species have feathery bipinnate foliage and fluffy globular white flowers.
They are very easy to grow in full sun to partial shade on just about any well drained soil. They can be cut back hard and will regenerate.
Propagation is from seed which germinates best if boiling water is poured over them then left to soak in water for 24 hours. Another option to loosen the seed coats is to scarify them for 15 minutes in sulfuric acid then leaves them to soak in water.
They can also be reproduced from half hardened cuttings.

Leucaena esculenta
A medium size tree. Some records include: largest on record - 50 feet with a trunk diameter of 3 feet.
The leaves are composed of leaflets, up to 1.5 inches.
They can tolerate drought for up to 7 months.

Leucaena glauca ( White Popinac )
Also called Leucaena leucocephala. A very fast growing tree native to south Florida, the Caribbean into South America. Some records include: 1 year - 10 feet; 2 years - 15 feet; 3 years - 20 feet ( average ); 3 years - 60 feet ( record ); 11 years - 40 feet ( average ); largest on record - 70 x 51 feet with a trunk diameter of 2 feet. The White Popinac typically only lives around 50 years.
A perennial up to 17 feet in Tucson where it freezes back in winter. It now occurs in the wild in southern Texas and California and have become extrmeley invasive in parts of the tropics where not native, including Hong Kong.
The bipinnate leaves, up to 12 inches in length, are composed of up to 80 leaflets, up to 1 inches.
The creamy-white globular flowers, up to an inch across, are borne in terminal clusters during spring.
The dark brown broad flat pods hang off of drooping clusters during summer.
The deep coppery young stems are not armed with spines.
Hardy zones 9 to 11 as a tree. As a perennial the roots are hardy to as low as 5 F if mulched.

Leucaena greggii
A fast growing thornless small tree.
Some records include: 3 years - 7 feet; 8 years - 12 feet; largest on record - 30 x 30 feet.
Hardy zones 8 to 10

Leucaena lanceolata
Some records include: 1 year - 6 feet; 2 years - 8 feet; 3 years - 14 feet- 4 years - 20 feet; 6 years - 25 feet; 11 years - 30 feet.

Leucaena leucocephala ( White Leadtree )
A very fast growing, upright, medium-sized, evergreen tree, reaching up to 66 feet, that is native from Mexico through much of Central America. Some records include: 3.5 years - 21 feet. It can become invasive in some regions where not native including southern Arizona.
The bipinnata leaves are up to 10 x 8 inches in size. The linear leaflets are up to 0.2 inches long. The foliage is mid-green.
The white to greenish-yellow, ball-shaped flowers are borne on terminal clusters during mid-spring.
They are followed by brown pods up to 6 inches long.
The bark is smooth and brownish-gray.
Hardy zones 9b to 11 ( freezes bad at 25 F but will resprout vigorously after dieback to temperatures as low as 16 F ). It requires an average yearly rainfall exceeding 20 inches. and thrives in full sun or partial shade.

* photo of unknown internet source


Leucaena pallens ( Tenaza )
Also called Havardia pallens. Typically an upright small tree to around 25 feet that is native from southern Texas into northeastern Mexico. It is typically evergreen though may become deciduous during extended drought. Some records include: largest on record - 41 x 25 feet.
It is a very beautiful landscape plants for the southwest U.S.
The feathery bipinnate leaves, up to 4 inches in length, are composed of 6 to 10 pairs of pinnae, each with 30 to 40 gray-green leaflets.
The fragrant white globular flowers, up to an inch, are borne in panicles at the branch tips during early to mid spring. The flowers attract Honey Bees and Hummingbirds.
They are followed by velvety, dark brown, hairy, flat, long narrow pods, up to 5 inches in length.
Hardy zones 9 to 10, tolerating as low as 15 F.

Leucaena pulverulenta ( Great Leadtree )
A rapid growing, medium size tree native from southern Texas to southern Mexico. Some records include: 1 year - 10 x 10 feet ( from seed ); 3 years - 25 x 20 feet; 10 years - 40 feet; largest on record - 60 x 63 feet with a trunk diameter of 3 feet. A perennial to 6.5 feet in Tucson where it freezes back in winter.
The bipinnate leaves, up to 10 inches in length, are composed of up to 840 leaflets, up to 0.3 inches.
The pods are up to 12 inches in length.
Hardy zones 9 to 10 tolerating as low as 14 F thriving anywhere with average annual rainfall over 24 inches. Severe branch dieback may occur below 22 F.

* historic archive photo


Leucaena pallida
Some records include: largest on record - 33 feet.

Leucaena retusa ( Littleleaf Leadtree )
A rounded, deciduous, small tree that is native from southeast New Mexico to central Texas; south to northern Mexico. Some records include: fastest recorded growth rate - 5 feet; 3 years - 7 feet; largest on record - 27 x 32 feet with a trunk diameter of 1.2 foot.
The bipinnate evergreen leaves, up to 5 ( very rarely 8 ) inches, are composed of 4 or 6 pinnae with leaflets, up to an inch in length.
The golden-orange globular flowers, up to 1.5 inches across ) are borne in clusters, continuously from mid spring to mid autumn as long as rainfall is abundant.
They are followed by flattened, narrow pods, up to 8 inches in length.
The attractive cinnamon bark is flaky.
Hardy zones 7 to 9, tolerating as low as -4 F in full sun to partial shade. Can be grown in zone 6 but dies to ground in severe winters. It is tolerant of alkaline soil and often grows in limestone bluffs in the wild.

* photo taken by Clarence A. Rechenthin @ USDA-NRCS PLANTS Database

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