Zanthoxylum americanum (Prickly Ash)

Plant Info
Also known as:
Genus:Zanthoxylum
Family:Rutaceae (Rue)
Life cycle:perennial woody
Origin:native
Habitat:part shade, shade; upland forest, floodplains, old fields, forest clearings
Bloom season:April - May
Plant height:15 to 20 feet
Wetland Indicator Status:GP: UPL MW: FACU NCNE: FACU
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

Pick an image for a larger view. See the glossary for icon descriptions.

Detailed Information

Flower: Flower shape: 5-petals Cluster type: round

[photo of male flowers] Male and female flowers are on separate plants in round clusters, about an inch across, in the leaf axils of 1-year-old branches, with 2 to 12 flowers in a cluster. Flowers are green to reddish with a short stalk and 5 egg-shaped petals that stay appressed about the base; sepals are absent. Male flowers have 5 erect yellow stamens.

[photo of female flowers] Female flowers have 3 to 5 dark green ovaries, each with a long pale style, the styles converging at the tip. Flowers emerge before the leaves in early to mid spring.

Leaves and stems: Leaf attachment: alternate Leaf type: compound

[photo of leaves] Leaves are alternate and pinnately compound, 5 to 10 inches long with 5 to 11 egg shaped to lance-elliptic leaflets and a few small prickles along the underside of the leaf stalk. Leaflets are 1 to 2 inches long and half as wide, nearly stalkless with nearly smooth edges. The upper surface is dark green and smooth or with sparse hairs (especially when young), the lower surface pale green and hairy. Leaves give off a lemony scent when crushed.

[photo of trunks] Branchlets are brown to gray and mostly smooth or with a few sparse hairs, and a pair of sharp, 1/3-inch prickles just below the leaf axils that persist on older branches. Older bark is mostly gray or brownish, mostly smooth or roughish. Twigs give off a lemony smell when broken.

Fruit: Fruit type: capsule/pod

[photo of fruit] Fruit is a red, finely textured, round to egg-shaped capsule up to ¼ inch long that splits in half when mature, revealing a shiny black seed. Fruits mature from late July through August.

Notes:

Prickly Ash is likely quite familiar to anyone who has spent time exploring or hunting in Minnesota's forests and woodlots. The spreading, shallow root system will send up new suckers when not inhibited by competing vegetation, creating dense thickets of nearly impenetrable brush that tears at the hands, face and clothing. All parts of the plant produce a fragrant and pungent citrus-like oil and it has been used for a number of medicinal purposes, notably tooth aches. Anyone who has tried chewing on a twig or just a few fruits quickly experiences its bitter, numbing, and throat grabbing properties. A few have questioned whether it actually inhibits tooth ache pain or is merely so obnoxious as to distract the sufferer from anything else in the mouth. Prickly Ash has no relationship to either our large forest ash species or the mountain ashes.

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More photos

Photos by K. Chayka taken at Rice Creek Trail Regional Park, Ramsey County. Photos courtesy Peter M. Dziuk taken in Anoka County.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Travis - Near Crosslake
on: 2015-10-17 00:05:07

South of the city of Crosslake is a bar called the Cedar Chest. South of the cedar chest is Big Pines Trail, the first left. The first right on Big Pines Trail leads to a logging road as the first turn off the left. What appears to be prickly ash grows on either side. I would love to hear of other locations.

Posted by: Mike S. - Hubbard County
on: 2016-02-24 12:55:06

We have this shrub spreading rapidly on our property. We first encountered in 10 years ago when clearing a trail through our woods. It was a small patch, less than 50 ft2. Now it has spread to close to 1/2 an acre. It has become inpenetrable and is shading out other shrubs. Our woods have alot of overmature basswood that is subject to blowdown, which is creating openings for prickly ash to spread.

Posted by: Rachel F - Ramsey County
on: 2016-08-19 21:00:59

I've found some here and there in the New Brighton/Arden Hills area, but none large enough to produce berries. It's the northernmost member of the citrus family and the berries are interchangeable with the Chinese spice known as "szechuan pepper." I did find some at Lebanon Hills recently that were producing berries, so we'll see if it's worth the numerous scratches and thorn pricks it took to harvest them!

Posted by: carrol - ramsey mn
on: 2018-06-18 22:56:47

didn't know what these were growing in yard weed line,noticed the lemon fragrance,thought citronella,was looking on line.than my brother figured it out,would normally cut down every year,placed some in certain areas,perrinnal come back every year,miniamal maint,appear very hardy.

Posted by: Sue - Dakota County
on: 2018-08-10 03:02:16

Lots of these berries in July at the Dakota Woods Dog Park in Rosemount, MN. I crushed a leaf for smell, and used my incisors to pierce a single berry for taste,then spit it out because I wasn't 100% sure about plant identity. Wow! What a tingling experience. It took me weeks to identify this plant though, because all my searches would just bring up spicebush. Glad I know what it is now!

Posted by: Grant
on: 2018-08-11 15:38:27

I bought a house in North Minneapolis near Victory Memorial Drive about 9 years ago. We thought these were blackthorn or hawthorn but found out that they are prickly ash. For me they were a nuisance. They were growing next to my front steps, along my south foundation and along the fence and retaining wall on the south. About six years ago I started cutting them down to the ground and by fall they were 10-15 feet or more high. This year a landscaping friend came and cut them down and dug out the roots, except for one growing out of a window well - he was afraid he’d break the widow accidentally while digging out the roots. So we waited uyil it started growing back and this week he sprayed it with something that is supposed to kill the plant entirely. We’ll see. Six years ago when I first started cutting them down, I took a couple of them and removed the thorns or prickles, whatever you want to call them - they are sharp!! Then I stripped the bark and made a nice walking stick and a cane. They are 2” diameter at top and 1-1/2” at bottom. The cane I made from one that had split into two branches - I sanded them to furniture finish smooth but left them natural (no staining). I cut the top of the cane just at the split which fits my hand very nicely. It was a great way to take something that was a nuisance and repurposed it in reuse.

Posted by: Melanie Peterson - Brainerd
on: 2018-09-07 13:23:44

Are these an invasive species? What can be done to safely get rid of them without poisoning the ground or wildlife? We have these growing on our property and I despise them!!!

Posted by: Laura - White Bear Lake
on: 2019-04-24 08:54:42

They are a host plant for the Giant swallowtail.

Posted by: luciearl - lake shore
on: 2019-05-08 23:12:48

I discovered about 5 trees a few years ago growing on my hill. It's native and produces berries, so kind to wildlife. Now reading how thick it gets and have been stabbed a few times with the prickers, thinking of cutting down. They're about 6 ft. tall.

Posted by: Mike - Dakota County
on: 2019-06-02 22:59:59

We have these growing in many locations on the family farm, most of which has not been actively farmed for 30+ years. I encounter it a lot when out removing buckthorn, and had considered removing it as well given its prickliness, but learned from one of the above comments that it’s a host plant for swallowtail butterflies, so it stays.

Posted by: Janet - Anoka County
on: 2021-05-10 09:05:43

We have these growing in shady areas on our property. It is a nice little tree but does have a tendency to spread and take over an area. As far as removal goes, they are easy to dig up. The roots are shallow and spread out sideways and then another plant grows up from the root, so when you pull one and pull the root sometimes you pull up a string of 2 or 3 trees at a time. Work with a partner, one person is digging while the other is pulling, and the work will go relatively quickly. I looked on line and saw that people are selling the dried berries and bark. Evidently it is used for flavoring and to promote good health.

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