A trellis provides a supportive structure that enables climbing plants to grow vertically, maximizing garden space and adding visual height to a landscape. This method of vertical gardening is highly effective for improving air circulation around foliage, which helps to reduce the incidence of moisture-related plant diseases. Trellising also makes harvesting fruits and vegetables easier, as the produce is held up off the ground and readily visible. By understanding the specific needs of the plant and the appropriate setup, gardeners can successfully guide growth upward to create a lush, living wall.
Selecting the Right Combination
The success of a trellised plant depends entirely on matching its natural climbing habit to the appropriate support structure. Plants climb in three primary ways: twining, clinging, and sprawling. Twining vines, such as pole beans and morning glories, wrap their stems or leaf petioles around thin supports, necessitating a trellis with slender wires, string, or narrow lattice pieces for the plant to coil around effectively.
Clinging vines, like English ivy, use aerial roots or adhesive pads to attach themselves directly to surfaces. While a trellis is not always required, it can guide initial growth. Sprawling or rambling plants, such as climbing roses and some tomato varieties, lack specialized structures and must be manually tied to the support. These sprawling plants require a robust structure with thicker bars or a solid wooden frame to support their weight. Heavy-producing vines like grapes, which develop thick, woody stems and significant fruit load, demand exceptionally sturdy trellises made of treated wood or metal to prevent structural failure.
Installation and Placement
Proper placement is crucial for the plant’s health and the structure’s stability. Most climbing plants require adequate sunlight, so position the trellis to receive the proper amount of direct sun, typically six to eight hours for fruiting varieties. The structure must be firmly anchored into the ground, often by sinking posts deep or using specialized ground anchors, to withstand strong winds and the mature weight of the foliage and fruit.
If the trellis is mounted against a wall or fence, maintain a gap between the support and the vertical surface. Use wooden battens or spacers to create an air space of 2 to 4 inches (5 to 10 centimeters). This gap prevents moisture accumulation, promotes air circulation, and allows twining shoots to wrap around the trellis without damaging the wall. For wooden trellises, keeping the bottom edge elevated 12 to 18 inches (30 to 45 centimeters) above the soil prevents rotting caused by constant moisture contact.
Training and Initial Attachment
Training begins when the plant is young and its stems are flexible. Gardeners should gently guide the primary stems onto the trellis soon after planting, rather than waiting for the plant to find the support independently. For twining vines, stems can be manually wrapped around the nearest support wire or post in their natural growth direction to initiate climbing.
Sprawling plants and heavy vines require soft ties to secure them to the structure. Materials such as strips of cloth, specialized plant tape, or rubber-coated wire are preferred because they are gentle on delicate stem tissues. Ensure the ties are looped loosely, allowing space for a finger between the tie and the stem, to accommodate thickening growth and prevent girdling. To encourage a dense, well-covered trellis, direct main stems horizontally along the lower supports; this stimulates lateral side shoots that fill out the vertical space.
Ongoing Care and Maintenance
Long-term management involves routine maintenance to ensure the plant and support structure remain healthy. Regular pruning is necessary to maintain the plant’s shape, prevent overcrowding, and encourage abundant flowering or fruiting. Pruning includes the seasonal removal of dead, damaged, or diseased canes, and the thinning of overly dense growth to improve light penetration and air flow within the canopy.
Pruning techniques vary by species; some plants flower on new growth and require a late winter or early spring cutback, while others flower on old wood and should be pruned immediately after blooming ends. Annually, before the plant puts on significant new growth, inspect the trellis for structural integrity. This check ensures all anchors and ties are secure so the trellis can bear the increasing weight of the mature plant.