Fraxinus nigra (Black Ash)

Plant Info
Also known as:
Family:Oleaceae (Olive)
Life cycle:perennial woody
Habitat:sun; moist to wet, mucky or peaty soil; floodplains, swamps, forest
Bloom season:May
Plant height:40 to 100 feet
Wetland Indicator Status:GP: FACW MW: FACW NCNE: FACW
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: indistinct Cluster type: panicle

[photo of male flowers] Flowers are borne on feathery, yellowish panicles, 1 to 2 inches long, from leaf axils of one-year-old branchlets. Male and female flowers occur on separate trees, both lacking petals and calyx, the male typically with just two, often red or purplish stamens, the female with only a single, reddish style. Flowers emerge before the leaves in spring.

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

[photo of leaves] Leaves are opposite and pinnately compound, 9 to 16 inches long with 7 to 13 oval to lance-elliptic leaflets. Leaflets are 3 to 5½ inches long and 1 to 2¼ inches wide, stalkless, with finely toothed edges and a long or abrupt, short taper to a pointed tip. The upper surface is dark green and smooth, the lower surface paler with short, matted brown hairs along the lower part of the midvein. The leaflets in the middle of the leaf are somewhat larger than those on the ends.

[photo of mature trunk] Branchlets are smooth, greenish brown to gray colored with light brown lenticels (pores) the first year. Branches turn brownish gray with corky ridges; older bark has thin, flat scales.

Fruit: Fruit type: seed without plume

[photo of fruit] Fruit is a single, winged seed (samara), narrowly oblong-elliptic, 1 to 1¾ inches long and ¼ to ½ inch wide, in open dangling clusters that can persist on the tree all winter. The wing extends all the way to the base with barely a bulge from the very flat seed inside.


Black Ash is Minnesota's most common ash species with over 600,000,000 trees, mostly in the northern half of the state. In moist upland forest it is a tall straight tree getting over 100 feet tall and up to 30 inches in diameter at breast height. But it is quite tolerant of wet, swampy sites though performs poorly, often creating large stands of scrappy, narrow-crowned trees with a lot of crown dieback. One of our last trees to leaf out in spring, it wears a brief yellow fall color before shedding its leaves in early autumn. It can be differentiated from our other two native ashes by its stalkless leaflets, scaly bark, and samaras that are very flat and winged all the way to the base. In winter the dormant buds are dark brown to nearly black, the terminal looking much like a deerhoof, and the lateral bud scars oval to slightly crescent shaped, similar to those of Green Ash (Fraxinus pennsylvanica), except for a short internode (gap) between the terminal bud and the first lateral buds below it (see photo below). The loss of this huge population of trees to emerald ash borer will likely have a profound effect upon the ecosystems it inhabits, especially on water quality in the watersheds it now helps protect.

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More photos

Photos courtesy Peter M. Dziuk taken in Anoka, Carlton and Lake counties.


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

Posted by: Janet - East Bethel (northern Anoka County)
on: 2021-06-20 15:18:23

I came here to identify what must be black ash, according to the leaves. We have several on our land growing like giant weeds! The stem holding the leaflets is hairy & reddish-brown on top, green on the bottom. The thin, center "trunk" is green, and also hairy. When I touch it, it has a stickiness and spicy(?) odor. They range in height from about 1'-4'. I haven't seen those characteristics mentioned about the black ash, so I thought I'd ask if that's typical of new growths. Love this site! Thanks to all who contribute to it!

Posted by: K. Chayka
on: 2021-06-20 15:33:19

Janet, chances are you have something other than black ash. Post some images on the Minnesota Wildflowers Facebook page and you may get confirmation.

Posted by: Scott Graham - North West Minnesota
on: 2022-04-19 18:06:15

I pray someone can help me. I am looking to plant some BLACK ASH trees, and, BEBB'S WILLOW trees on my property. Can someone please tell me where I can find these to purchase?

Posted by: K Chayka
on: 2022-04-19 18:16:05

Scott, you probably won't find anyone selling ash trees with emerald ash borer making its way across the state. Bebb's willow may be easier to find but maybe not by much. The DNR maintains a list of native plant suppliers for different regions but I don't know how comprehensive it is, or whether there are nurseries in the list or just landscapers and restoration specialists. If none of those vendors have what you're looking for, perhaps one knows who does.

Posted by: Luciearl - Lake Shore
on: 2022-07-14 15:27:06

Scott Graham, If you were looking for ash seeds, merely walking along a trail, you may find thousands of clusters hanging from trees this time of year.I just grabbed a cluster. Still trying to decide whether its black ash or not. Definitely ash. Looks similar to the butternut trees, but leaves are narrower.

Posted by: Alex Heegaard-LeGros - Minneapolis
on: 2023-01-01 13:00:25

Scott Graham- Out Back Nursery in Hastings lists Bebb's Willow in their catalog. A relative of mine has some land up near Pine River with some sections of fairly pure Black Ash Swamp with some large Black Ash (at least large as far as I have seen). When they get big/old in these swampy conditions the flaring base of the trees, covered in moss, are really striking. A few I would struggle to get my arms around in size. Trying to enjoy them while they last as EAB cruises north.

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