Ostrya virginiana (Ironwood)

Plant Info
Also known as: American Hop-hornbeam, Eastern Hop-hornbeam
Family:Betulaceae (Birch)
Life cycle:perennial woody
Habitat:part shade, shade, sun; average to dry soil; hardwood forest, upland slopes, wooded bluffs, old fields
Bloom season:April - May
Plant height:20 to 50 feet
Wetland Indicator Status:GP: FACU 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: indistinct Cluster type: raceme Cluster type: spike

[photo of winter male catkins] Male and female flowers are borne separately on the same tree (monoecious) in dangling clusters called catkins. Male catkins are in groups of 1 to 4 from the tips of 1-year-old branchlets, ¾ to 2¼ inch long, developing in fall, the flowers an appressed, reddish-brown scale-like bract that turns greenish and expands out in spring.

[photo of female catkin] Female catkins are 1/8 to ½ inch long at the tips of first year branchlets, the flowers with a spreading, green bract and thread-like red styles.

Leaves and bark: Leaf attachment: alternate Leaf type: simple

[photo of leaves] Leaves are simple and alternate, soft to the touch, the blade oval-elliptic, 2 to 5 inches long, 1 to 2 inches wide, tapered to a pointed tip, the base rounded and symmetrical, sharply double-toothed along the edges. The upper surface is dark green with fine, velvety hairs, lower surface lighter green, hairy, especially along the veins, with tufts of hairs in vein axils. Leaf stalks are hairy, often glandular hairy.

[photo of twig] Twigs are brown to reddish with downy hairs and scattered white lenticils (pores), are often glandular hairy, and become smooth the second year.

[photo of mature trunk] Older bark is grayish brown, thin and finely textured with vertical, rectangular plates. Trunks can reach 14 inches diameter.

Fruit: Fruit type: capsule/pod

[photo of mature fruit] The fruit is a small, oval nutlet enclosed in an inflated, papery sac 1/3 to 1 inch long. The mature fruiting catkin is similar in appearance to those of hops with a number of sacs in a pendulous series 1¼ to 2 inches long.


Ironwood is a common understory tree throughout Minnesota's upland deciduous forest. Highly shade tolerant, it is slow growing in understories where it rarely grows into the canopy. Its branches are often broadly horizontal and retained fairly close to the ground. In open sunnier sites it can grow quite quickly, attaining a height of some stature. While most often it has only a single trunk, its not uncommon to find multi-trunked specimens with a broad, spreading crown. Its name of Ironwood comes from its extremely hard, durable wood. Like our oak species, it typically retains a number of dried brown leaves through the winter months, which is termed marcescent. Ironwood is an excellent small, urban shade garden species.

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More photos

Photos courtesy Peter M. Dziuk taken in Anoka, Hennepin, Ramsey and Wright counties.


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

Posted by: Keith A - Mpls
on: 2017-04-19 07:13:43

Came home to find a freshly planted ironwood tree on the boulevard (4-18-17, Cooper neighborhood). The city of Mpls is replacing Ash trees infected by the emerald ash borer. This field guide provides a great introduction to a welcome neighborhood addition.

Posted by: Joseph Capecchi - Kanabec county
on: 2018-06-18 21:51:01

Near the lake interspersed among the White Pines

Posted by: Mary Elizabeth Ince - Webb Lake, Woodrow Township, Cass County
on: 2018-08-03 23:22:14

We have ironwood trees in the understory of our 15 acre woods on the lakeshore. Our woods are primarily aspen interspersed with birch, white and red oak, maple, basswood, eastern white pine. I have not observed any large ironwoods but would like to encourage some that we have to grow larger by opening the spaces around them. I find the horizontal branching and fruiting catkins very attractive.

Posted by: Kim Cordahl - Fergus Falls
on: 2018-09-21 08:41:27

I would like to post pictures of the most incredible ironwood clusters I have ever seen. Can I get some help to share these?

Posted by: K. Chayka
on: 2018-09-21 17:46:52

Kim, you could post them on the Minnesota Wildflowers Facebook page.

Posted by: Gary - Carlton County
on: 2018-11-08 23:51:33

Occasional in the tall shrub layer in mixed red oak-sugar maple-basswood-aspen forests.

Posted by: Karen Updegraff - Lake County
on: 2019-03-07 08:45:12

Understory trees 1-4m tall in upland (hilly) site, 16 of 55-09w, with bigtooth and quaking aspen, balsam fir, spruce. ID based on twigs and persistent dead leaves.

Posted by: Kathy &Doug Wood - Stearns county in a pine woods north of Sartell along the Mi
on: 2020-02-13 02:13:58

We have a number of these... love the bark.

Posted by: Linda S - Duluth
on: 2021-05-18 07:33:24

Ordered 10 from St Louis County Native Tree Sale some 10 years ago and planted in our yard and neighbor's. Doing well

Posted by: Mark Ladwig - Savage (SW suburb of Mpls)
on: 2021-08-14 11:57:36

We live next to a large wooded area. We have a lot of Ironwood trees around us. Over just the past two or three months, many of these Ironwoods have died. Several others now have branches that are withering and appear likely to die too. We are saddened to be losing these wonderful trees. Is it related to the drought? Or might something else be going on? Any advice on how to evaluate and save our Ironwoods is immensely appreciated.

Posted by: K. Chayka
on: 2021-08-14 18:01:30

Mark, you should contact an arborist, or at least a Master Gardener.

Posted by: Renay Leone - eastern Sherburne County
on: 2021-09-21 18:51:42

I finally realized this is what I am seeing in our old pasture/oak savanna area, along with maples, basswoods and of course bur oaks. The main tree seems to be seeding 'babies' about 30 feet out from the main tree - is this normal/done by birds?

Posted by: K. Chayka
on: 2021-09-22 08:21:40

Renay, older ironwood trees have been known to root sucker, but seed also spreads by wind, water and critters.

Posted by: D Haeg - Western Hennepin County
on: 2022-03-01 11:18:45

I am considering planting 4 foot bareroot Ironwood trees in an area that gets sun and shade during the primary growing season. Our plan is to remove/kill established Buckthorn and use the Ironwood as replacement for both visual appeal and privacy. How far apart should I plant these 4 foot bareroot Ironwood so they both flourish and screen? Thanks!

Posted by: K. Chayka
on: 2022-03-01 12:28:38

D Haeg, I suggest consulting with the nursery that is supplying the ironwood.

Posted by: Sherman in Duluth - In Duluth near the South end of Swan Lake Road
on: 2022-04-18 14:51:23

About 10 years ago I noticed a tree in Duluth on the West side of Swan Lake Rd, that was just loaded with BRIGHT WHITE flowers that on close inspection, looked like "Hops" flowers. I had walked along that road for many years and had never seen ANY flowers there. I looked it up and identified it as a Hophornbeam. In all the years since then, it hasn't put on a display like that one year. Most years the tree doesn't even seem to flower, though last summer it flowered with fewer flowers that weren't very white so they were barely noticeable near the edge of the Maple / Basswood forest. People are currently tapping the nearby Maple trees to make Maple syrup.

Posted by: Andy - Minneapolis
on: 2022-07-10 16:47:58

The City planted an ironwood in the boulevard in front of my house about three years ago. It lives in the afternoon shadow of a big bur oak, in sandy soil, and seems to like it there. Some articles I've read say that ironwoods can't tolerate salt and shouldn't be planted along streets. Others say that it's a great boulevard tree. So far, it looks healthy. I still water it every two weeks or so when the weather gets hot. It seems to have just recently become well-rooted, so I don't plan to water it in future years (unless it's changing color, losing leaves, seriously wilting, etc.).

Posted by: Jeanne - North Minneapolis
on: 2023-04-20 11:11:22

The city planted one of these in our boulevard yesterday (4/19). It will get sun throughout the day but a lot of shade in the late afternoon and evening. It will be shaded by oaks and a birch and a maple.

Posted by: Cynthia - Chisago County
on: 2023-09-21 23:50:42

Which bird species tend to prefer ironwood trees for perching, feeding, nesting, etc.? I read that they may provide cavity nesting opportunities.

Posted by: John Saxhaug - Northern
on: 2023-12-17 18:02:53

Where can I get Ironwood seedlings?

Posted by: K Chayka
on: 2023-12-17 18:15:46

John, Minnesota Wildflowers does not track who sells what so check with native plant nurseries.

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