Friday, October 22, 2010

Native Plant of the Week: Ironwood ~ Ostrya virginiana

Ironwood ~ Ostrya virginiana
Other Common Name: Hop Hornbeam

The Ironwood trees are becoming more apparent in Minnesota woods right now as most trees have shed their leaves, Ironwoods tend to hold onto their leaves much longer into the winter months. These dark brown leaves provide some nice interest in the woodland landscape in the winter.

We have planted several Ironwood trees in our yard, many in the backyard where we reclaimed the lawn and have started to turn it back into a woodland. This area is very dry and shaded and they're doing really well.

Ironwoods are a very adaptable tree. They typically grow as an understory tree and can tolerate a lot of shade. They are fairly slow growing, can reach 50 feet in height but a more typical size is 25-35 feet.

This summer was the first summer in the 4 years since we converted the lawn where we started to get Ironwood seedlings coming up.

We have several mature Ironwoods over the backyard fence and now that we have a better growing medium built up (leaf litter & humus) seedlings are starting to germinate.

Ironwoods have very attractive hop-like papery seed pods that form in mid to late June after flowering. The male catkin flowers elongate in May and are quite conspicuous hanging downwards from the branches. The female flowers are more hidden and not as noticeable.

These papery seed pods dry and turn from creamy white in color to a light brown later in the season. The seeds drop in the fall and winter months.

Ironwood gets its common name from its tough wood that is very hard to saw. The bark is another nice feature which is coarse with flat raised strips.

Ironwood is by no mean a straight upright tree. Its main leader will often take a few twists and turns as it grows upwards. The branching is very flat or horizontal which gives it an overall unique form in the woods or landscape.

If you have some openings in your shaded landscape for Ironwood I would highly recommend this native tree. It makes a great replacement to the invasive European Buckthorn.

Ironwood is native to Eastern North America, from Saskatchewan south to Texas and eastwards.