These hazelnuts are grown from seeds from Yamhill European Hazelnut (Corylus avellana), an early ripening variety used in commercial production. Yamhill consistently produces some of the highest quality hazelnuts out there. Additionally, Yamhill is immune or completely resistant to Eastern Filbert Blight.
These bare-root seedlings are grown in air-pruner beds, and they are between 1 and 3 feet tall.
Photo credit: I, Colae, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/>, via Wikimedia Commons