IRONWOOD (Ostrya virginiana)
a.k.a. AMERICAN HOPHORNBEAM

HEIGHT/WIDTH AT MATURITY: 25-40’/20-30’; SOMEWHAT PYRAMIDAL WHEN YOUNG, GROWING TO FORM ROUND OR OVAL OUTLINE WITH AGE.
SOIL/SUN REQUIREMENTS: PREFERS MOIST, WELL-DRAINED, SLIGHTLY ACIDIC SOIL WHEN YOUNG. CAN TOLERATE DRIER CONDITIONS WITH AGE.
BARK: GREYISH, IN NARROW, VERTICAL STRIPS. VERY INTERESTING TEXTURE. SUPERB COMPLIMENT TO VERTICAL PERENNIALS SUCH AS IRIS.
FALL COLOR: LIGHT GREEN IN SUMMER, CHANGING TO YELLOW IN FALL, SOMETIMES HOLDS LEAVES IN WINTER FOR SCREENING.
FRUIT: MONOECIOUS; A NUTLET (APRIL) ENCLOSED IN A HOP-LIKE SAC; STAMINATE MALE CATKINS, USUALLY SETS OF THREE.

When choosing a featured tree I want to recommend a tree that’s hardy and reliable in Minnesota. I want to offer up a plant which will provide a visual treat as well as one that’s not going to be a time or money sink in regards to insect or disease management. But I also like to call homeowners’ attention to a tree that isn’t usually the first, second, or even third off the tongue of a typical landscape or nursery professional. It’s not the tree for everybody. But it should be the tree for more homeowners. And that’s why we’re looking at the ironwood.

Ironwood is a Minnesota native which occurs naturally as an understory tree, often companion to mature oaks. It is a relatively slow growing tree, averaging 10-15’ over a 15 year period. For use in the urban forest, all this translates as: it’s a good tree for a part shade situation; has great bark for winter interest, especially as a focal point on the edge of a natural/woodland setting. Ironwood will do fine in full sun. It’s not tolerant of salt spray, so it’s not a good tree for heavy traffic boulevards.

Ironwood is not widely available in the nursery trade, so you may have to hunt a bit. It performs best when planted in spring. As always, a smaller diameter tree will take less time to establish an adequate root system, so don’t be tempted by a larger specimen. Ironwood is sometimes available as a bare root plant. Be sure to keep it watered properly, especially the first three seasons.

Check below for sources. Shine a spotlight on an under-used landscape gem; plant an ironwood this weekend!

http://www.hort.uconn.edu/plants/o/ostvir/ostvir1.html
http://www.museum.state.il.us/muslink/forest/htmls/trees/O-virginiana.html http://www.dnr.state.oh.us/forestry/Education/ohiotrees/hophornbeam.htm

Photos courtesy of The Ohio Department of Natural Resources and The Ohio State University Department of Horticulture and Crop Science, 2002©