A shop-bought trellis panel is a flimsy thing. It flexes in the first decent gust, splits where the staples went in, and rarely matches the wall you had in mind. Build your own from treated battens and galvanised wire and you get something stiffer, cheaper and cut to the size you actually want — a frame a climbing plant can hold on to for years.
The method below suits a wall or a freestanding run at the end of a border. Allow an afternoon for a fence up to about four metres long. Most of that time goes on digging.
What You'll Need
- 75 x 75mm pressure-treated posts, or 50 x 50mm for a run under 1.8m tall
- 38 x 38mm pressure-treated battens for rails and frame
- 2mm galvanised wire — plastic-coated if you prefer a softer look
- Screw-in vine eyes, galvanised staples and a couple of turnbuckles
- Exterior-grade wood screws or coach screws
- Postcrete, or a dry mix of cement and ballast
- Soft garden twine for tying in
You'll want a spirit level, a string line, a saw, a drill, a spade, a lump hammer, wire cutters and an adjustable spanner. Buy pressure-treated timber rather than untreated and hoping for the best. If you cut it, brush preservative on the cut ends, because that's where rot starts. Choose a plant-safe preservative and follow the label.
Pick the Spot and Set the Size
Match the fence to the plant, not the other way round. Clematis, jasmine and ivy will all cover a 1.8m frame happily, but ivy left alone will keep going. If you're growing against a wall, a fence standing about 300mm off the masonry gives you air circulation and room to get behind the plants for pruning and painting.
Sun matters too. Most clematis want their roots in shade and their tops in sun; jasmine flowers best with a decent amount of light. Check the eventual spread before you commit. A clematis that reaches three metres needs a frame at least that wide, or you'll be extending it next summer.
Two checks before you dig. First, look for buried cables, pipes and drainage — check your utility plans or run a cable avoidance tool along the line. Second, if you're fixing to a wall, make sure it's yours. A neighbour's wall or a shared boundary needs a conversation first, and a listed building or a property in a conservation area may need consent before anything is attached.
Set the Posts
Dig holes about 600mm deep and 250mm wide. Spacing of 1.5 to 2 metres between posts is plenty for a wire trellis; go closer if you're building tall on an exposed site. Firm the bottom of each hole with the end of a post, then drop the post in.
Set the two end posts first. Get them upright with a spirit level and brace them, then run a string line between them at the top and part-way down. The posts in between should just touch the line and sit level with each other at the top. Check each one for plumb in both directions — a post that looks fine from the front can lean badly from the side.
Fill with Postcrete or a dry cement mix, tamp it down, and shape the top of the concrete so it slopes away from the post. Water then runs off rather than sitting against the timber. Leave it to go off for a day before loading the frame. On a long run, two people make light work of lifting posts; one is a wrestling match.
Build the Frame
With the posts firm, fix horizontal rails: one at the top, one at the bottom about 150mm above ground level, and a middle rail if the fence is over 1.8m. Rails go on the face of the posts, screwed with two exterior-grade screws per joint. Predrill to stop the batten splitting, particularly near the ends.
For a wall-mounted version, fix vertical battens to the wall at 600mm centres using frame fixings or masonry screws and plugs, spacing them off the wall with short blocks of batten so air can move behind the timber. Then screw your rails across them. Check the frame for square by measuring the diagonals — if the two measurements match, you have a true rectangle.
Run the Wires
Screw vine eyes into the posts at the height of each wire. Start 300mm above ground and work up in 300mm steps. Go tighter, around 200 to 250mm, if clematis is the main planting, since its leaf stalks need something fine to wrap around. Jasmine twines rather than clings, so give it horizontal wires plus a few verticals to climb.
- Thread the wire through the eyes, pulling it hand-tight as you go.
- Fit a turnbuckle at one end so you can take up slack later without restringing the run.
- Without a turnbuckle, pull the wire taut with pliers, wrap it once around the end post and staple it firmly.
- Repeat for each wire, working upwards.
Don't overdo the tension. Wire that's drum-tight will pull the frame out of shape in a hot summer. Galvanised wire will outlast the timber; plastic-coated wire is kinder to young stems and less likely to scorch leaves in strong sun, but check it each year for cracking.
Plant and Train
Plant about 300 to 450mm out from the base of the fence, not right against it. The soil there is drier and the roots will have room to spread. Lean long stems in towards the wires and tie them with soft twine in a figure of eight, so the stem isn't pinched against the wire.
New growth needs guidance for the first season. Push jasmine and clematis shoots sideways along the wires rather than letting them bunch at the bottom — a fan shape covers the frame faster. Ivy is self-clinging once established and will grip the timber on its own, but keep an eye on it. It will happily find its way into gutters, mortar joints and window frames, and redirecting a young shoot is far easier than unpicking a mature one. Water regularly through the first summer; climbing plants put on a lot of growth above ground and need the moisture to match.
Keeping It in Shape
Walk the fence once a year, ideally in late winter before growth takes off. Check the wires for slack and re-tension them, and replace any staples that have pulled. Look at the timber where it meets the ground, since that's the first place rot shows, and treat bare or cut patches with preservative. Prune the plant to fit the frame rather than letting it run past the top and flop, and tie in new shoots while they're still flexible.
None of this is difficult. The result is a fence that costs less than a set of panels, holds its shape in the wind and can be repaired one wire at a time. Give it a season and the plants will do the rest.
Photo: Rahime Gül / Pexels