Ostrya virginiana


This member of the birch family is one of our rarest native trees. It is a relatively short-lived and small tree. It grows to be 40 feet (12.5 m) tall and 1 foot (30 cm) in diameter, although it rarely reaches this size. It is a slender tree, with leaves like yellow birch, although ironwood leaves have teeth of two different sizes. The bark of ironwood is light brown and scaly, shredding off in vertical strips. It has simple alternating leaves with jagged teeth along the margins.


Ironwood prefers rich, moist soil and grows best in dappled light. Often found near rivers, ironwood thrives as an understory tree in our Island forests.


In September, small, greenish seeds can be collected from the trees. The seeds are enclosed in a papery sac, with many sacs being held together in a cluster similar to true hops. When ready for harvest, the clusters will start to turn brown and some will drop to the ground. Pick seeds off the tree if possible. When you separate the seed from the sac, you should wear thin gloves and a mask, since the sacs have fiberglass-like hairs that wind up in your fingers and probably shouldn’t be inhaled.

Plant seeds every 2 inches (5 cm) in rows 4 inches (10 cm) apart, at a depth of 1/8 inch (3 mm) and mulch for the winter. If the bed is in full sun, some form of shading should be provided during the growing season.

Most seeds take two years to germinate but any that germinate the first summer should be transplanted to another bed. This avoids the problem of having older plants in the bed when seedlings are germinating the second year.

Wildlife Uses:

The buds and catkins of ironwood are used by ruffed grouse and red squirrels. The seeds are eaten by purple finch, rose-breasted grosbeak, and other birds.

Areas of Usage:

We should do all we can to conserve this rare species, as it is critical that we keep as many seeds sources as possible. The presence of ironwood should be carefully considered when developing a plan for your woodland. It is an excellent choice for under-planting or inter-planting after a mixed wood thinning, and will help provide diversity of height in older forests. As well, it is good for landscape plantings where there is some shade.

Additional Information:

Ironwood is rare throughout this province. It has been seen in the western section of the province in the Haliburton area. Small numbers are found in Cavendish.

Ironwood is sometimes called hop hornbeam, as its clusters of seeds resemble those of true hops. The clusters of papery seed sacs are hairy and quite light. They can float away from the parent tree in the wind, they are carried away by birds, and they can float quite a distance downstream before lodging themselves on the bank.

Ironwood produces one of the hardest and toughest native woods and is used for vehicle stock, tool handles and spring poles. Because of its small size it has traditionally not been viewed as an important source of timber products.

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