Build a Trellis and Plant Supports: Growing Upward on a Budget

Every garden has more space than its floor area suggests, and it is all vertical. Walls, fences, and the air above beds are unused growing room in most gardens, and the structures that unlock them — a grid of wires, a cane wigwam, a home-made obelisk — are among the cheapest and simplest things you can build.

The payoff is disproportionate. Climbing beans crop heavily from a square metre of ground; a rose trained horizontally on wires flowers along its whole length instead of at the top; a fence carrying a climber becomes a green boundary; and perennials supported before they flop stay upright through the summer storms that would otherwise flatten them. This guide covers the structures, the fixings, and the one rule that matters most: build it before the plant needs it.

Match the Support to How the Plant Climbs

The FAQ makes the point that this matters more than the choice of wires or trellis. Plants climb in fundamentally different ways, and giving one the wrong support wastes both:

The practical consequence: roses need tying in, beans need something to spiral, and ivy needs nothing. Buying trellis for a self-clinging climber is money wasted, and giving a rose nothing to be tied to is why so many climbing roses end up as a bare-legged mess with flowers at gutter height.

Wall Wires: The Cheapest and Best System

For most wall climbers, a grid of horizontal wires beats trellis panels — cheaper, less obtrusive, easily extended, and it disappears behind the plant.

1. Mark horizontal lines up the wall, roughly 40–50 cm apart, spanning the width you want covered.
2. Fix vine eyes into the wall along each line, every 1–2 metres — using proper masonry fixings, into brick rather than crumbling mortar.
3. Run galvanised wire through the eyes and tension it. Galvanised outlasts plastic-coated in the long term.
4. Keep the wire a few centimetres off the wall, which is what the vine eyes are for — air circulation and something for twiners to wrap around.
5. Train stems horizontally along the wires as the plant grows, which is the single most valuable trick for climbing roses and many other climbers: horizontal stems flower along their length, vertical ones only at the tip.

Building a Wall Trellis

Where you want a decorative panel or instant structure, trellis is straightforward — with one critical detail from the FAQ:

• Mount it on battens so it stands a few centimetres off the wall. This allows airflow, gives twiners something to grip, and lets you unscrew the panel and lower it with the plant attached to maintain the wall behind. A trellis screwed flat to brick traps damp and makes future maintenance impossible.
• Fix into the wall properly, or on fences into the posts and rails rather than the thin panel, which will not hold a mature climber.
• Consider the fence problem: fences move and eventually need replacing, so a long-lived vigorous climber is often better on a wall or a freestanding structure.
• Check before drilling for cables and pipes, and keep clear of vents and damp-proof courses.
• Make your own from battens if you want a specific size — a simple lattice or a series of horizontal battens screwed onto two vertical ones costs a fraction of a bought panel.

Freestanding Structures

• Wigwams — the classic bean support: five to seven canes pushed firmly into the soil in a circle, drawn together and tied at the top. Fast, effective, and reusable for years. Space canes generously so plants get light.
• A-frames — two rows of canes crossed and tied to a horizontal ridge cane, giving a longer run for beans and peas with good access down the middle.
• Obelisks — a more decorative four-sided frame, easily made from four battens with horizontal cross pieces; excellent for sweet peas, clematis and roses in borders and large pots.
• Arches and pergolas — a bigger project, but the same principles: solid ground fixing, sound joints, and a structure strong enough for a mature plant, which is far heavier than a young one.
• Netting and pea sticks — the simplest of all. Netting stretched between two posts supports peas and sweet peas; twiggy prunings pushed into the ground are the traditional pea support and cost nothing.

Anchor everything properly. A structure covered in growth acts as a sail — the commonest failure is not the structure breaking but the whole thing blowing over in late summer when it is fully clothed and the ground is dry.

Supports for Perennials and Vegetables

Not everything that needs support is a climber. Tall perennials and fruiting vegetables need holding up, and the FAQ's timing rule matters most here:

• Perennial supports go in during spring — grow-through rings, linked stakes, or a grid of string between canes. The plant grows through and hides them entirely; installed in July around a collapsed plant, they never look right.
• Twiggy sticks saved from winter pruning, pushed in among emerging perennials, are the traditional method and the cheapest — and they look natural because they are.
• Cordon tomatoes need a single sturdy cane or string per plant, tied in as they grow.
• Dahlias and gladioli get stakes at planting, since pushing one in later risks spearing the tuber — a point the summer bulb guide makes explicitly.
• Fruit and heavy crops may need branch support in a good year; a forked stick under a laden branch is a legitimate solution.

Screening and Privacy Without a Fence

One of the most valuable uses of a support structure is creating privacy where a wall or hedge is impractical. A trellis panel or a run of posts and wires, planted with a climber, screens a seating area, hides a bin store or shields a boundary at a fraction of the cost and bulk of fencing — and unlike a fence, it improves each year. The practical points: screening structures need to be genuinely well anchored, because a screen covered in growth catches wind like a sail; choose an evergreen climber if you want year-round screening, or accept a deciduous one that gives summer privacy when you actually sit outside; and check height restrictions and boundary rules before building anything tall on a boundary, since the same neighbourly considerations the hedge guide raises apply to structures too. A trellis topper added to an existing fence is the cheapest version of all, adding height and a growing surface without replacing anything.

Materials and Longevity

The main longevity lesson: timber fails where it meets the ground. Setting posts on metal spikes, on gravel, or in post shoes rather than sinking bare timber into soil extends their life by years.

Supports in Containers

Pots present a specific problem: there is nowhere to anchor a support properly, and a tall structure in a container is top-heavy by definition. The workable solutions are to use a heavy pot — terracotta or glazed rather than lightweight plastic, exactly where the container guide's weight point becomes an advantage; to push canes or an obelisk right down to the base of the pot rather than just into the surface compost; to tie the structure back to a wall, railing or fence wherever one is available, which is by far the most secure option; and to accept a smaller structure than you would use in the ground. Balconies add wind exposure to the problem, so a supported plant in a pot on an exposed balcony needs both a heavy container and a physical tie to the building. Where none of that is possible, choose plants that stay compact rather than fighting physics with a wigwam that will eventually go over.

Tying In: The Detail That Matters

• Tie loosely, in a figure of eight around stem and support, so the stem can thicken without being strangled.
• Use soft materials — garden twine, soft ties, strips of old fabric. Wire and cable ties cut into stems as they grow.
• Check ties every season. A tie that fitted last spring can girdle a stem by the following year — a common cause of mysteriously dying branches on trained plants.
• Tie in as the plant grows, not once at the end of the season; young flexible stems train easily, and old rigid ones do not.
• Spread stems out rather than bunching them, so light reaches the whole plant and air circulates — the same argument the pruning and disease guides make.

A Simple Obelisk You Can Build in an Hour

If you want one project from this guide, make it an obelisk — it suits borders and large containers, supports sweet peas, clematis, climbing roses and beans, and looks considerably better than a bundle of canes. Cut four lengths of batten for the uprights, all the same length, and a set of shorter cross pieces in decreasing lengths for each tier. Lay two uprights on the ground, splayed slightly apart at the bottom, and screw the longest cross piece near the base and progressively shorter ones up the length — then repeat for the other two uprights to make a matching side. Stand the two sides up, splay them into a square, and join them with cross pieces at the same heights. Cap the top by screwing the four uprights together or adding a decorative finial. Treat or paint it if you want longevity, and set it on the soil surface with the legs pushed in rather than sinking the timber deep, which is what makes obelisks rot.

The Classic Mistakes

1. Installing supports after the plant flops, instead of before it needs them.
2. Trellis screwed flat to a wall, trapping damp and blocking maintenance.
3. Fixing into fence panels rather than posts, and losing the lot in a gale.
4. Under-building: a structure sized for a young plant collapses under a mature one.
5. Not anchoring, and watching a fully grown wigwam blow over in August.
6. Tight ties and wire that strangle stems.
7. Growing climbing roses vertically instead of training them horizontally.

The Bottom Line

Vertical space is free space, and the structures that unlock it are simple, cheap and quick to build. Match the support to how the plant climbs — thin supports for twiners and tendrils, tie-in systems for roses, nothing at all for self-clingers. On walls, galvanised wires on vine eyes beat trellis for most climbers; where you use trellis, mount it on battens with a gap behind for air and access. Build wigwams, obelisks and frames from canes, prunings or battens as the job demands, anchor everything against wind, and set timber off the ground where you can. Then get the supports in before planting rather than after flopping, tie loosely with soft twine, and check the ties every season. A weekend's work and very little money turns a flat garden into a three-dimensional one.