Hazelnut trees require careful planning before planting to ensure long-term success. The distance between trees is a primary consideration, as proper spacing supports canopy development, maximizes nut production, and allows for necessary orchard management. There is no universal spacing measurement for all hazelnuts; the ideal layout depends entirely on the specific variety chosen and the intended purpose of the planting.
Determining Spacing Based on Hazelnut Type
Hazelnut varieties fall into two distinct categories based on their natural growth habits, which directly dictate the required planting distance. Bush or shrub varieties, such as the native American hazelnut, are naturally multi-stemmed and form dense thickets through root suckering. These varieties thrive when planted closer together, typically requiring 8 to 10 feet between the center of each plant for a dense, productive row. For a thicket or hedgerow that maximizes privacy, this distance can be reduced to 6 or 7 feet to encourage canopy overlap.
Single-trunk tree varieties, including most European and hybrid commercial cultivars, are managed to grow as larger, individual trees. These require significantly wider spacing to accommodate their mature size and allow access for maintenance and harvesting equipment. A common standard for these vigorous trees is 20-foot by 20-foot square spacing, though a range of 15 to 20 feet apart is often used. The specific mature size of the chosen cultivar determines the permanent distance, ensuring the trees do not become overcrowded.
Adjusting Spacing for Specific Uses
The base spacing recommendations may be modified depending on the overall goal of the planting. In high-density commercial orchards, growers sometimes opt for tighter rectangular spacing, such as 10 by 20 feet, to maximize early yields. This approach requires intensive management and specialized pruning to maintain tree size and prevent excessive shading between rows.
For home planting or backyard use, choosing the wider end of the recommended range, such as 18 to 20 feet, is often beneficial. This allows each individual tree ample room to grow to its full potential, provides easy access for hand-harvesting, and promotes better air circulation. If the primary objective is to form a solid, impenetrable hedge or screen, the spacing for shrub types can be tightened further to as little as 4 to 6 feet between plants. This creates a continuous barrier rather than focusing on maximizing nut production.
The Role of Pollination in Orchard Layout
Hazelnut trees are monoecious, bearing separate male (catkins) and female flowers on the same plant. However, they are self-incompatible and require cross-pollination to set nuts. Successful nut production depends on planting a compatible pollinizer whose pollen shed overlaps with the female flower receptivity of the main crop. This necessitates strategic placement of the pollinizer trees.
Hazelnuts are exclusively wind-pollinated, influencing the arrangement of varieties. Since the density of the pollen cloud decreases significantly with distance, nut set may decline if a tree is more than 50 feet from a pollinizer. A common layout strategy in orchards is to dedicate 8 to 12% of the total trees to pollinizers, often by planting them every third tree in every third row. Alternatively, a designated pollinizer row can be planted every ten rows of the main cultivar, ensuring prevailing winds carry the necessary pollen.
Site Preparation and Initial Planting Technique
Once the appropriate spacing and layout have been determined, the focus shifts to preparing the site for tree establishment. Hazelnuts perform best in well-drained soils, as they are susceptible to root rot and water stagnation, and they generally prefer a soil pH ranging between 6.0 and 7.0. If the existing soil is heavy clay or poorly drained, amending it or ensuring a raised planting bed is advisable before digging.
The planting hole should be dug wide enough, ideally two to three times the width of the root ball, to allow the roots to spread easily. However, the hole should be no deeper than the root system to prevent the plant from settling too low. It is important to ensure the crown or the graft union remains at or slightly above the final soil line, as planting too deep can stunt growth and lead to health issues. After backfilling, thoroughly water the area to settle the soil and eliminate air pockets. Follow this with a layer of mulch to conserve moisture and suppress weeds.