Depending on how you look at it, the hazelnut, or filbert, is a shrub or a tree. The plant grows with a bushy habit and it's multi-stemmed. But hazelnuts can also reach higher than 15 feet, the cut-off height for shrubs. In the United States, commercial growers train hazelnut to a single trunk and call it a tree. If you sow a hazelnut seed, do so knowing that you won't end up with a replica of the mother plant. Hazelnut seeds are among those that don't germinate true to type.
Prepare a well-drained site that's in full sun in the fall. Break up the surface with a shovel and pickaxe, and incorporate 2 inches of compost into the soil. Rake the planting area to smooth it out.
Make a hole 2 inches deep, and sow the hazelnut to chill it through the winter, in a process called stratification. Cover the seed with topsoil. Don't water it.
Install a screen mesh over the seeded area to keep wildlife from digging it up. Bury the screen's edges into the ground and weigh them with rocks or bricks. Leave the seed undisturbed until it sprouts in the spring.
Remove the screen mesh as soon as you notice a seedling.
Give your hazelnut plant 1 inch of water a week, and refrain from fertilising it in its first year.
Install a trunk sleeve around the hazelnut to protect it from sunburn in the winter. Insert a tree stake next to the tree and tie the plant if you're concerned about strong winds.
Build a 3-inch-deep mulch ring around the tree with wood chips, dead leaves or other mulch material. Leave about 6 inches of space between the organic matter and the base of the tree so there's no physical contact. Pull any weeds that sprout through the mulch.
Fertilise the hazelnut tree every spring starting in the second year. Select a high-nitrogen brand, and apply it according to the manufacturer's specifications.
Plant a second hazelnut tree of a different variety within 100 feet of the first one for cross-pollination. Without it, your tree won't bear fruit. Cross-pollinated hazelnuts begin to produce nuts when they're 4 or 5 years old.