Wisteria vines are among the most spectacular and fragrant of garden flowers. However, they are also invasive and can actually uproot the foundations of a house. These heavy vines need heavy-duty trellises set deeply into the ground for support.
While many wisteria are grown next to porches where they can climb up a post and trail along railings and the roof, they can also be grown on a sturdy trellis in any sunny and protected spot in your landscape. A favourite support for either Chinese or Japanese wisteria is an overhead trellis, which allows the heavy, fragrant lavender flower clusters to hang down in the spring and summer and the seed pods in the winter.
A heavy-duty trellis requires sturdy 5 x 10 cm (2 x 4 inch) posts. These should be redwood, cedar or cypress as these woods resist underground rot, pests and disease. You can also use pressure-treated timber. If you use other wood above ground, give it two coats of exterior paint.
Build a four-sided frame in the dimensions you want your overhead canopy. Attach preconstructed lattice to the frame with galvanised nails or weave 1.3 cm (1/2 inch) laths between the frame posts. Reinforce the corners with galvanised steel corner brackets.
Anchor four 5 x 10 cm (2 x 4 inch) outside posts at least 60 cm (2 feet) into the ground, spacing them to fit the corners of your canopy. A common height is 1.8 to 2.4 m (6 to 8 feet), but wisteria can grow higher than a house. Use a ladder to set the frame on top of these posts and attach it securely with galvanised nails.
The canopy can arch over a path in the garden, span a flowerbed or frame and shade a window. Regular pruning will train the wisteria to grow up one of the posts and spread across the canopy, dangling its flower clusters through the lattice.
For a sturdy, low-budget wisteria trellis, attach panels of welded wire mesh (sold at hardware shops for concrete reinforcing) or chicken wire to an existing fence.
The wire mesh is sold in 1.2 x 1.8 m (4 foot by 6 foot) panels with 10 cm (4 inch) square holes (which cost about £3 each). Secure the panels to horizontal and vertical wooden fence posts with half-inch staples. Or wire the panels securely to a wrought iron or chain link fence.
As a bonus, the wisteria will turn your fence into a colourful and fragrant feature of your landscape.