Tuesday, December 8, 2009

Tuesday's Trees- Carpinus caroliniana

-- Ironwood, American Hornbeam, Musclewood- this tree goes by many names.

My first introduction to this tree was at the Adkins Arboretum along the eastern shore of Maryland. The visit was part of our Master Gardener trip. The group I walked through the woods with had a few Tree Stewards in training and it seemed like we were in heaven.

Many of the Ironwood we came across were very young trees and making the ID with these young trees was primarily with the growth structure of the trunk. The leaves are so similar to beech and birch trees. The leaves are double serrated, oblong, ovate. They occur alternately from the twig. It is green during the growing season and in the fall it turns orange to red to yellow. Quite often the leaves hang on through the winter. Here is a link to Sweetbay's web posting with beautiful fall color.

It is a slow growing tree, reaching heights of 20- 30 feet with similar spread. Typically it is an understory tree and as such has an open canopy. If planted in more sun the canopy is denser. This native tree is hardy from zones 3- 9. Often seen as a multi-stemmed tree, the stems are crooked, smooth and light gray in color. The trunk has the appearance of a muscular limb…. One of the ways we were able to make our identification on a young tree was to feel the base of the trunk. It does feel like someone has a flexed muscle.

C. caroliniana is a monoecious tree with both male and female catkins in the spring. The fruit is a long nutlet and it a food source for birds. Large seed production occurs every 3- 5 years. The germination rate is low. The Silvics manual is an excellent reference guide for this tree.
Common names for many plants are often used for more than one plant variety. I first learned this tree to be an Ironwood, but there is another tree called Ironwood—Ostrya virginiana. Another tree in the birch family, also a crooked trunked tree…but this Ironwood has ridged bark, unlike the American Hornbeam (Carpinus caroliniana) that has a very smooth trunk.
Wonderful resources for the Carpinus caroliniana-
MOBOT- wonderful pictures
What Tree Is This site- nice quick reference
UNCONN- concise information
USDA data sheet- great links to other information
NCState- quick list of information, no photo
Virginia Tech fact sheet easy to print fact sheet to carry with you
Forestry Service a great reference

Next tree- Magnolia grandiflora
Sorry for the delay in getting this posted, life happens.


  1. Janet,
    Just about a month ago we found several Ironwoods on our property. I knew they were in the woods here lower down the creek. Enjoyed this post. I'm looking forward to the Magnolia grandifolia post, but how can you describe the fragrance?

  2. This is a nice native tree. It seems to form little colonies that look quite handsome. It seems to like to grow in specific conditions. It doesn't seed all over the place.

    True to its name if you plan on cutting one down you had better sharpen your saw.

  3. Ironwood is a lovely understory native tree. I love the look of the trunk.

  4. Hello,

    OK, I just love that you have to feel it's base and they feel like flexed muscles. Isn't that kind of like feeling a flexed arm muscle?

    We have a desert tree called Ironwood (Olneya tesota), but it is quite different. Your Ironwood is quite beautiful. I will post about my Ironwood in February when it starts flowering.

  5. I wasn't familiar with the scientific name of this tree - but when you said 'musclewood' and I saw the muscular trunk, boy, it's familiar! Thanks for the info.

  6. This is a tree I have probably mis-identified as a birch when I've seen it. Interesting that you have to feel the trunk to help identify it. Thanks for all the info, Janet!

  7. Hi Randy, how nice that you have some ironwood on your property. Are they very mature?

    Hi Chris, it does form colonies, it is an interesting tree with the crooked trunks of muscular arms. It is a hard tree to transplant, but does well from container to new site.

    Hi Sweetbay, thanks for allowing the link! I like the trunk too.

    Hi Noelle, it is like feeling a flexed arm! I look forward to seeing your Ironwood....oh those common names. :-)

    Hi Pam, glad it rang a bell for you. Common names are funny things.

    Hi Rose, Beech, birch, elm and hornbeams have such similar leaves it makes me crazy to try and figure out who is who!!

  8. Great trunks on these trees Janet! I'm sure you've increased your knowledge base about trees a zillion times over doing this series.


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