Zanthoxlum - Prickly Ash

A widespread genus of 250 spiny trees and shrubs native to all of the worlds continents except Europe ( though often planted there ).
Many have fine timber which is used for cabinet making. Most have handsome aromatic foliage. The fruits on many are dried and used for spices.
*** These trees are essential for diets of and survival of the Thoas, Giant and Spicebush Swallowtail Butterflies. ( http://en.wikipedia.org/wiki/Giant_swallowtail )

Most prefer full sun to partial shade on moist, fertile, well drained soil.
Pruning is rarely necessary except for pruning young trees to shape.
Propagation is from seed, rooted suckers and cuttings.



Zanthoxylum ailanthoides ( Ailanthus Zanthox )
A very fast growing, prickly, large deciduous tree native to eastern China, Korea and Japan, that can reach up to 60 feet. Some records include: fastest recorded growth rate - 10 feet; 10 years - 33 x 30 feet; largest on record - 66 x 60 feet with a trunk diameter of 4 feet. Massive old trees are known to grow in Korea. The canopy is broadly spreading and dome shaped and the branches are gnarled. That combined with the extremely attractive tropical looking foliage makes this an excellent tree for the landscape though rare and difficult to find.
The large, pinnate leaves reach up to 40 inches in length and are composed of up to 23 oblong, pointed, finely serrated, opposite arranged leaflets that are up to 6 x 2 ( rarely 4 ) inches in size. The thick foliage is glossy bright to blue-green above and blue green beneath.
The small, green white flowers are borne in terminal panicles up to 6 inches wide in spring to summer. They are followed by small green fruits that enclose a black seed.
The bark is gray and green striped with black spined protuberances.
Hardy zones 7 to 10 on any fertile, moist, well drained soil in full sun or partial shade. Easy to transplant and also easy to grow. It requires long hot summers for the wood to ripen and is not hardy in most of the British Isles.

Zanthoxylum americanum ( Common Prickly Ash )
A fast growing, spiny-stemmed, handsome, small tree to 20 feet. Some records include: fastest recorded growth rate - 3 feet; largest on record - 40 x 30 feet with a trunk diameter of 1 foot. Rarely lives as much as 40 years though this tree often forms thickets with much longer living rootstock. The Common Pricly Ash is native to North America ( from eastern North Dakota to northern Wisconsin to parts of Michigan's Upper Peninsula to Alpena, Michigan to Wiarton, Ontario to Petawawa, Ontario to southeastern Quebec to southern New Hampshire; south to Oklahoma to western Maryland to Massachussetts ). It is critically endangered in Maryland, Tennessee, Louisiana, Alabama and Georgia. Extinct in New Hampshire and threatened in Quebec. In the Windsor/Essex County, Ontario region; it was abundant along the Canard River Valley, at Point Pelee, the Lake Erie islands as well as the Ohio shore during the 1800s. It was also abundant at Detroit during that time. It is a favored plant for the larvae of the Giant Swallowtail Butterfly.
The aromatic, foliage is pinnate up to 12 inches in length and composed of 5 to 11 ( rarely 13 ) oval leaflets up to 3 x 1 ( rarely over 2.5 ) inches in size. The foliage is glossy deep green.
The tiny, yellow flowers are borne on axilliary clusters, up to 2 inches across, before the foliage during mid-spring.
They are followed by black berries, up to 0.2 inches in length.
The stout twigs are light brown and spiny.
The bark is silvery. The wood is 35 pounds per square foot.
Thrives in full sun or partial shade on almost any fertile soil from zones 3 to 8.
Rarely bothered by pests or disease.
The only pruning needed is removing lower branches to train as tree and removing dead wood. Propagation is by seed in autumn or root cuttings in late winter.

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

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

* photos taken on Sep 18 2016 @ Patuxent Research Refuge, Laurel, MD

* common prickly-ash in Port Rowan, ON

Zanthoxylum capensis
A tree native to South Africa that reaches up to 50 feet in height.
Its leaves reach up to 8 inches in length and are composed of up to 20 leaflets up to 2.5 inches in length.
Hardy zones 9 +

Zanthoxylum clava-hercules ( Hercules Club )
A rapid growing, small rounded tree to 30 feet or more in height that is native ( though rare ) to the southern U.S. from Oklahoma to coastal Virginia and south. It is endangered in Virginia, North Carolina and Georgia. Some records include: Largest on record - 66 x 50 feet with a trunk diameter of 2.5 feet. A very large tree is known to grow in the Holly Springs Cemetary in Nocogdoches County, Texas. A tree far north of its natural range is known to grow in Norristown, PA.
The foliage is alternately arranged though the leaflets are opposite on the leaf stems. The very fragrant leaves are up to 8 or rarely even 16 inches in length. They are composed of 7 to 19 leaflets up to 3 x 1 inches in size. The foliage is very glossy deep green above and paler below. The leaf stems are spiny and the foliage lasts very late into the fall.
The greenish male and female flowers are borne in terminal clusters up to 5 x 3 inches on separate trees. They are followed by brown, wrinkled capsules up to 0.8 inches that split open to release one black seed.
The bark is light gray and studded with short spines. The brown twigs are armed with spines up to 0.5 inches long.
Thrives in sun or partial shade on any fertile though preferably moist sandy soil. The Hercules Club Ash is hardy from zones 5 to 10 and is tolerant of floods and heat.

* photo of unknown internet source

* photo taken by W.D. Brush @ USDA-NRCS PLANTS Database

* photos taken @ U.S. Botanical Garden, Wash., DC on Aug 25 2014

* photos taken on Aug 24 2017 @ U.S. Botanic Garden, Wash. DC.

* historic archive photo

Zanthoxylum coriaceum ( Biscayne Prickly-Ash )
A small, evergreen tree, up to 23 feet tall that is native to southeast Florida and the Caribbean. It is endangered in Florida. Some records include: fastest recorded growth rate - 4 feet; tallest on record - 33 feet. The leaves are up to 8 inches in length and are composed of 5 to 13 leaflets up to 2.5 x 1 inch. The foliage is glossy mid-green. The spines are reddish-brown and the bark is smooth and gray mottled. Hardy in the tropics only ( zones 10 + ).

Zanthoxlum cubense ( Cuban Zanthox )
Native to Cuba and reaching up to 45 feet in height; this Prickly Ash is suitable for the tropics ( zone 10 + ) only.

Zanthoxylum dipetalum
An endangered Hawaiian native that reaches a maximum size of 50 x 50 feet with a trunk diameter of 1 foot. Its tropical looking foliage is composed of up to 7 leaflets up to 12 x 5 inches in size. Hardy only zones 10 + where there is no frost and rainfall is abundant.

Zanthoxylum fagara ( Lime Prickly Ash )
A moderate growing, small evergreen tree native to Mexico, southern Texas and southern Florida that can reach up to 40 feet. Some records include: fastest recorded growth rate - 3 feet; largest on record - 60 x 40 feet with a trunk diameter of 2 feet. The Lime Pricly Ash is also excellent as a dense hedge rather than tree. It is valuable as a food source of the Giant Swallowtail Butterfly.
The foliage is alternately arranged though the leaflets are opposite on the leaf stems. The leaves are up to 4 inches in length and are composed of 7 to 9 leaflets up to 1.2 x 0.5 inches in size. The foliage is very glossy, bright green. The leaf stems are winged.
The yellow-green male and female flowers are borne in axilliary clusters on separate trees. They are followed by brown, warty capsules that contain one black seed.
The bark is thin, gray and warty. The brownish twigs are spiny.
Thrives in sun or partial shade on any fertile soil. The Lime Prickly Ash is hardy from zones 8 to 11 and is very heat, salt and drought tolerant.

Zanthoxylum flavum ( Satinwood )
An evergreen, small tree to 30 x 35 feet or rarely more that is native to south Florida, the Caribbean and Bahamas. It was once common in southern Florida but is now endangered due to environmental destruction. The largest on record is 66 x 75 feet with a trunk diameter of 31 inches. It makes an excellent shade tree.
The foliage is alternately arranged though the leaflets are opposite on the leaf stems. The leaves are up to 10 inches in length and are composed of 5 to 11 smooth-margined, elliptical leaflets up to 4 x 1.5 ( rarely over 3 ) inches in size. The leathery foliage is glossy deep green above and paler below. The leaf stems are spiny and the foliage lasts very late into the fall.
The greenish male and female flowers are borne in terminal clusters up to 5 x 3 inches on separate trees. They are followed by brown, wrinkled capsules up to 0.8 inches that split open to release one black seed.
The bark is light brown and smooth. The brown twigs have NO spines.
Thrives in sun or partial shade on any fertile though preferably moist sandy soil. The Satinwood is only hardy in the tropics from zone 10 and up. It is moderately salt tolerant.

* historic archive photo

Zanthoxylum gilletti ( African Satinwood )
Native to the mountains of Zimbabwe in Africa and reaches up to 100 feet. Should be planted only in zone 10 at high elevations ( ex. mounatins in Mexico and central South America )

Zanthoxylum hawaiensis
An endangered tropical small tree native to Hawaii. The largest on record is only 26 x 26 feet with a trunk diameter of 1 foot.

Zanthoxylum hirsutum ( Texas Prickly Ash )
Closely related to Zanthoxylum clava-hercules and similar in many ways. It is native from southern Oklahoma to central Texas and is exceptionally tolerant of drought. It is also smaller typically less than 20 x 20 feet with a trunk diameter under 6 inches though sometimes much larger with the record being 51 x 30 feet with a trunk diameter of 1.5 feet.
The leaves are up to 5 inches in length and are composed of 5 to 9 leaflets up to 2 x 0.8 inches in size.
Hardy zones 7 to 9.

Zanthoxylum martinicensis
A fast growing tree native to the Puerto Rico and the Caribbean reaching a height of 66 feet or rarely much more to 90 feet with a trunk diameter of 2.5 feet.
The leaves are composed of up to 19 leaflets up to 5 inches in length.
Hardy zones 10 and warmer only.

Zanthoxylum mayo
A large tree reaching a maximum height of 100 feet with a trunk diameter of 6.6 feet, that is native to the Juan Ferdinez Islands in Chile. The leaves are up to 7 inches in length and are composed of up to 18 leaflets that are up to 2 inches in length. Hardiness unknown but certainly restricted to mild maritime climates.

Zanthoxylum nova-zelandiae
An old name for what is correctly now known as Hedycarya arborea.
Native to New Zealand and only grows in mild maritime climates. Largest on record - 40 feet in height with a trunk diameter of 2 feet.

Zanthoxylum piperitum ( Japanese Pepper )
A very beautiful, moderate growing, spiny, dense, bushy, rounded small tree, reaching around 18 x 20 feet, that is native to mountains of China, Korea and most of Japan. Some records include: fastest recorded growth rate - 5 feet; largest on record - 33 x 25 feet.
The foliage is very aromatic and smells like Green Peppers. The pinnate leaves, up to 7 inches in length, are composed of 13 to 23 oval leaflets up to 1.5 x 1 or rarely 2.5 x 1.5 inches in size. The foliage is glossy, very deep green, turning to bright yellow during autumn.
The small, yellow-green flowers are borne in clusters up to 6 inches across during spring.
They are followed by tiny, orange berries.
The bark is beige to reddish-brown.
Hardy zones 5 to 7 in full sun or partial shade on almost any fertile soil. Rarely bothered by pests or disease. The only pruning needed is removing lower branches to train as tree and removing dead wood. Propagation is by seed in autumn or root cuttings in late winter.

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





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


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

* photos taken on Aug 15 2014 at Maryland Zoo, Baltimore, MD

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

Zanthoxylum planispinum
Also called Zanthoxylum alatum. A large, deciduous open shrub to small tree, native to China, Korea and Japan, that reaches a maximum size of 20 x 15 ( rarely over 13 ) feet with a trunk diameter of 8 inches. The stems have spreading prickles up to 0.7 inches in length.
The pinnate leaves, up to 10 inches in length, are composed of 3 or 5 stem clasping, finely-toothed, oblong leaflets up to 6 x 1.3 inches in size. The foliage lasts very late in the fall up until Christmas. The attractive foliage is glossy mid-green. The winged leaf rachis is spined underneath.
The very small, pale yellow flowers are borne in small clusters, up to 1.5 inches wide, during spring.
They are followed by very small, warty, red berries, up to 0.2 inches across.
Hardy zones 6 to 7.

Zanthoxylum schinifolium ( Korean Peppertree )
A spiny, deciduous small tree that is native to eastern China, Korea and Japan. Largest on record - 25 x 28 feet.
The pinnate foliage, up to 10 inches in length, are composed of up to 21 elliptical leaflets up to 2.8 x 1 ( rarely over 2 ) inches in size. The very attractive foliage is luxuriant glossy mid green.
The pale yellowish-green flowers are borne in showy flat-topped clusters during early summer.
Hardy zones 5 to 9 ( use seed source from Liaoning Prov., China in zone 5 ) in full sun to partial shade.

'Inermis'
Thornless; otherwise identical to species.

Zanthoxylum simulans ( Flatspine Prickly Ash )
A spiny, spreading, moderate growing, large bushy, rounded shrub native to mountains of China that can become tree like with age. Some records include: fastest recorded growth rate - 5 feet ( rarely more than 2 feet ); largest on record - 28 x 31 feet with a trunk diameter of 1 foot. A very large tree of 23 x 31 feet grows at Morris Arboretum in Philadelphia, PA.
The deciduous, aromatic foliage up to 9 inches in length is composed of 7 to 11 sparsely toothed, ovate leaflets that are up to 2 x 1 inches in size. The foliage is glossy bright green with prickles beneath. The leaves turn to orange and burgundy in fall. The leafstalk is spined. A cultivar has been reported to have purplish young foliage.
The tiny yellow flowers are borne in clusters up to 2.5 inches across in May.
The flowers are followed by very attractive, small, orange-red rounded berries in late summer. The flowers are followed by very aromatic, round, warty fruits up to 0.25 inches across that are green and ripen to scarlet-red. The fruits eventually dry and split open to release shiny, black seeds.
The bark is gray with spiny protuberances and the stems carry triangular flattened spines.
Thrives in full sun or partial shade on almost any fertile soil from zones 5 to 10. It thrives in both eastern North America as well as being one of the few species that thrives in the Pacific Northwest.
Rarely bothered by pests or disease.
The only pruning needed is removing lower branches to train as tree and removing dead wood. Propagation is by seed in autumn or root cuttings in late winter.

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

* photo taken on Apr 25 2016 @ U.S. National Arboretum, DC

* photos taken on Aug 30 2021 @ U.S. National Arboretum, Washington, DC