Most trellises fail for one of two reasons: the plant cannot grip it, or it cannot hold the plant. A clematis will sit at the bottom of a chunky cedar lattice all summer, and a wisteria will pull a garden-centre arch out of the ground in three years. Here is how to match the two, and how to make a trellis or arbor survive an Ontario winter.
Match the trellis to how the plant climbs
| How it climbs | Examples | Support it needs |
|---|---|---|
| Leaf stalks (petioles) wrap around supports | Clematis | Thin wire, mesh or narrow slats, under about 1/2 to 3/4 in across |
| Tendrils | Grapes, sweet peas | Wire, twine or light lattice, 3/4 in or less |
| Twining stems | Honeysuckle, wisteria, hops | Posts, poles or wires the stem can wrap; strength to match the vine |
| Adhesive pads or rootlets | Virginia creeper, Boston ivy, climbing hydrangea | A solid surface, ideally a separate panel or wall, not wood siding |
| No grip (scramblers) | Climbing roses | Horizontal wires or a sturdy frame, with stems tied loosely |
Climbing methods from University of Illinois Extension and University of Maryland Extension.
Ontario climbers and how much they weigh on a structure
| Climber | Size and weight | Best structure |
|---|---|---|
| Clematis | Light | Wire or mesh trellis, obelisk, or wire run up an arbor post |
| Climbing roses | Medium, thorny | Arbor or fan trellis with horizontal wires |
| Honeysuckle (vine) | Medium | Arbor or post-mounted trellis |
| Hops | Fast, dies back to the ground each winter | Tall posts with twine or wire |
| Grapes | Heavy when fruiting | Post and wire system, or a sturdy pergola |
| Climbing hydrangea | Heavy, up to about 30 ft (UConn) | Masonry wall or a heavy freestanding structure |
| Kentucky wisteria | Very heavy, 20 to 30 ft (Morton Arboretum) | Pergola or arbor with posts at least 4x4, set below frost |
| Virginia creeper | Vigorous | Its own panel or a masonry wall, kept off wood siding |
Trellis, arch or arbor?
| Type | What it is | Typical cost |
|---|---|---|
| Wall or fence trellis | A flat panel of slats, lattice or wire, mounted on stand-offs | $150 - $500 per panel installed |
| Metal garden arch | Light tubular arch on ground stakes | Under $100 on the shelf (a 7 ft arch was $86.99 at Home Depot Canada, Oct 2026) |
| Cedar arbor kit | Walk-through arbor with side trellis panels | About $929 for a Vita cedar arbor at Home Depot Canada, plus installation |
| Custom cedar arbor | Built on site, posts set below frost, sized to the path or gate | $1,200 - $3,500 installed |
| Pergola | A roofed frame of beams and rafters | $4,500 - $9,000 installed; see our pergola cost guide |
A light metal arch is fine for annual vines, clematis and sweet peas. Anything that lives for decades and gets heavy needs a wood or steel structure on proper posts.
Anchoring a trellis or arbor for an Ontario winter
- Arbor posts below frost. Set wood posts like fence posts, about 4 ft into the ground in concrete, or on footings with metal post bases. Short posts heave, and an arbor that leans 5 degrees looks like it is falling over.
- Stake metal arches deep. The stakes that come in the box are too short for an exposed spot. A loaded arch catches wind like a sail. Anchor it to short concrete-set posts or longer ground anchors.
- Stand-offs on walls and fences. Mount trellis panels 2 to 3 in off the surface so air moves behind the plant and the wood or siding can dry.
- Rot-resistant materials. Cedar, pressure-treated wood rated for ground contact, galvanized wire or powder-coated steel.
- No snow loads on top. Keep flat tops open so snow falls through, or build them strong enough to carry it.
How to make a simple garden trellis
- Build a frame of 2x2 cedar, sized to the plant: about 2 ft wide by 6 ft high suits a single clematis.
- For clematis or grapes, run galvanized wire or stainless cable across the frame every 8 to 12 in, or staple on a sheet of galvanized mesh. Thick slats alone are too wide for them to grip.
- For roses, run horizontal wires about 12 to 18 in apart and tie the canes to them as they grow.
- Fix the trellis to 2 to 3 in wood stand-offs on the wall or fence, or set its legs into the ground on two short posts.
- Plant 12 to 18 in out from the base, where the soil is not dried out by the wall, and lean the young stems toward the trellis.
By-laws: does a trellis count as fence height?
It depends on the town. Hamilton's Fence By-law 10-142 counts latticework as part of the fence and measures height to the highest point, so lattice on top of a 6 ft fence can push it over the 2.0 m limit. An archway forming an entrance may go 0.4 m over the limit. Oakville's Fences and Privacy Screens By-law 2002-034 says a fence does not include a trellis or arbour, and lets an entrance archway reach 2.3 m. Small open structures like a garden arbor generally do not need a building permit. Hamilton, for example, exempts a detached accessory structure for a house up to 15 m2 with no plumbing. Zoning setbacks still apply.
Frequently asked questions
What is the best trellis for clematis?
One with thin supports it can wrap its leaf stalks around: wire, cable, mesh or narrow slats under about 1/2 to 3/4 in across. Wide lattice slats are too thick for clematis to grip without help.
What is the difference between a trellis and an arbor?
A trellis is a flat or freestanding support for a climbing plant. An arbor is a walk-through structure, usually an arch or a small roofed frame over a path or gate, often with trellis panels on the sides.
How much does a garden arbor cost?
Under $100 for a light metal arch, about $900 for a cedar arbor kit at Canadian stores in 2026, and $1,200 to $3,500 for a custom cedar arbor installed on posts set below frost.
Can I put a trellis on top of my fence?
Often yes, but in Hamilton lattice counts toward fence height, so the fence and lattice together must stay within the 2.0 m backyard limit. Oakville's fence by-law excludes a trellis or arbour. Check your town's by-law first.
Will wisteria grow in Ontario?
Kentucky wisteria is rated to USDA zone 5 and grows 20 to 30 ft, so it can work in sheltered spots in Hamilton and Halton. It is very heavy and needs a pergola or arbor built on posts set below frost, not a light trellis.
Do climbing vines damage fences?
Vigorous vines can. They hold moisture against the wood, add weight and push boards apart. Clinging vines like Virginia creeper can also damage wood siding. Give them their own trellis set a few inches off the fence or wall.