Pleaching is an ancient horticultural practice used to transform trees into flat, geometric screens or walls. This technique involves training the branches of young trees to grow along a rigid, two-dimensional plane, often parallel to a wall or freestanding structure. The result is a highly architectural form that provides both structure and foliage to a landscape setting. This method has historical roots dating back centuries to European gardening traditions, where it was employed in formalized gardens and orchards for both aesthetic and practical purposes.
The Art of Pleaching: Training and Weaving
The creation of a pleached tree begins with the selection of young, whip-like stock, which is then subjected to specific initial pruning cuts to encourage lateral branching. These cuts are strategically placed to stimulate dormant buds, forcing growth to occur along the desired two-dimensional plane rather than allowing the natural, three-dimensional canopy to develop. A sturdy, rigid framework made of wire, bamboo, or wood is immediately installed to provide the necessary support for the future trained structure. This trellis acts as a template, guiding the horizontal growth of the selected primary branches.
Once the lateral shoots emerge, they are carefully tied to the horizontal lines of the support framework using flexible material that will not girdle the developing wood. As the branches extend, they are continually manipulated and tied down to maintain the strict horizontal alignment required for the flat screen effect. Vertical growth is consistently suppressed, diverting the tree’s energetic resources into the controlled, horizontal extension of the main arms.
A defining technique in the most formal pleached screens is inarching, or approach grafting, which physically fuses adjacent branches. This involves carefully removing a thin layer of bark and cambium from two crossing branches and binding the wounds together tightly. Over time, the vascular tissues of the two separate branches merge, creating a permanent, living connection between the trees in the row. This results in a unified, structurally stable screen that no longer relies solely on external ties for its geometric integrity.
Landscape Function and Aesthetic Applications
Pleached trees serve a distinct function in landscape design, acting as living architectural elements that introduce defined vertical structure into a space. Their precisely trained forms allow designers to establish clear, linear boundaries without the visual heaviness of a solid wall or hedge. These screens are often used to segment large garden areas, creating smaller, more intimate “rooms” within the overall landscape composition. The resulting effect is one of ordered formality, linking the garden to the clean lines of human design.
One of the most practical applications is the creation of elevated privacy screening, where the foliage plane is maintained well above standard fence height. This technique provides effective sight-line blockage for upper-story windows or terraces while preserving open space at ground level. Historically, pleaching was used to form formal avenues, known as allees, lining walkways or carriage drives to create a shaded, tunnel-like experience.
Aesthetically, the geometric structure of pleached trees offers a strong visual anchor throughout the year, especially in temperate regions. When deciduous species drop their leaves, the intricate, grid-like pattern of the bare branches remains, offering compelling winter interest and revealing the underlying training artistry. The dense, uniform foliage plane during the growing season contributes a sophisticated texture that contrasts sharply with the looser forms of surrounding natural plantings.
Selecting Suitable Tree Species
Selecting the correct species is necessary for the long-term success of a pleached screen. The ideal candidate must have young wood that is flexible enough to be bent and tied horizontally without damage during the initial training phase. Furthermore, the tree must tolerate the rigorous and repetitive heavy pruning required annually to maintain the two-dimensional form. Species that naturally produce numerous lateral buds and dense foliage are preferred for creating an opaque screen.
The common lime (Tilia europaea or Tilia cordata) is the most historically favored species due to its vigorous growth and ability to withstand severe pruning. European hornbeam (Carpinus betulus) is another excellent choice, prized for its dense branching structure and retention of dead leaves through winter, which enhances its screening capability. Beech (Fagus sylvatica) is also frequently used, particularly for its smooth bark and its habit of holding onto its foliage well into the dormant season, providing extended visual cover.
Maintaining the Pleached Form
Once the geometric form is established, maintenance is necessary to prevent the tree from reverting to its natural growth habit. The primary task involves hard pruning during the dormant season, before new buds break. This annual structural pruning removes any branches that have grown out of the two-dimensional plane, reinforcing the framework and promoting healthy new growth. This cutback is often severe, removing the majority of the previous year’s growth from the horizontal arms.
In addition to the winter pruning, clipping during the summer growing season is often required, particularly for fast-growing species. This summer trim focuses on shearing the soft, new shoots to maintain the crisp, defined outline of the foliage plane. Managing the vertical leader growth is also important; while the main trunk must be allowed to gain height until the desired screen level is reached, any subsequent vertical shoots must be removed. Failure to suppress these vertical components will quickly compromise the flat, screen-like integrity of the pleached form.
The regularity of this pruning schedule ensures the density and uniformity of the screen, forcing the tree’s energy into producing a tight network of short, lateral spurs along the main horizontal branches. A well-maintained pleached row will exhibit a consistent, opaque surface from end to end.