Driveway Weed Killer: Safe Ways to Clear Weeds by Surface

The best driveway weed killer is often not a chemical at all: on most drives, scraping out the weeds and the dirt they grow in, then keeping the surface swept, works better and lasts longer. Where a weedkiller is needed, use an authorised product labelled for paths and hard surfaces, spray only the weeds, and follow the label exactly, because that is a legal requirement. If weeds keep coming back through the middle of a drive, the surface or the base has usually failed.

Why weeds grow on a driveway

Weeds need two things: a seed and somewhere to root. Seeds blow in or spread from nearby lawns and borders all the time, so what decides whether you get weeds is where they can root. In order of how often we see it:

1. Debris on the surface. Soil, leaves and grit build up in corners, along edges and in low spots. Seeds germinate in that layer, on top of the drive, not through it.

2. Edges. Where a drive meets a lawn, border or fence, roots creep in from the side, especially if there is no proper edging.

3. Joints. Block paving and slabs have sand-filled joints that weeds love. Loose gravel is even easier for them.

4. Cracks and failed surfaces. Weeds coming up through the middle of a tarmac or concrete drive are growing through cracks. That points to a thin surface, a poor sub-base, or no membrane under it.

The fix depends on which of those you have, so look before you spray. On the drives we lay for homeowners across driveways in Wolverhampton and the West Midlands, weak edges, joints and cracks are designed out from the start, which is what the last section of this post is about.

Clearing weeds without chemicals

The RHS does not support using weedkillers and recommends other methods first. On a drive, these work well:

• Weeding knife: a narrow hooked blade drawn along cracks and edges cuts and lifts the weed, root and all.

• Stiff or wire brush: clears moss and seedlings and the dirt they grow in. Sweep it away afterwards, or it just reseeds.

• Hand pulling deep-rooted weeds: a narrow weeding tool gets out dandelions and docks better than pulling.

• Regular sweeping: the most effective prevention there is. No debris, nowhere to germinate.

The government's guidance on permeable drives also recommends removing weeds by hand or with a weed burner, and says not to use weedkiller on a permeable surface at all. Weed burners carry a fire risk and need care around hedges, fences and cars. Keep them off tarmac and resin, which are both held together by binders that soften with heat.

Using a driveway weedkiller safely and legally

If you do use a chemical, the rules are straightforward:

• Use an authorised product. Weedkillers sold for home use carry a five-digit MAPP number on the label. The HSE says that if a product is not on its garden products database, it is probably no longer authorised and would be illegal to use. Check old bottles in the shed.

• Follow the label. You are legally required to use a pesticide as the label instructs: the right product for the job, the right dilution, the right place.

• Use amateur products only. By law, professional products must only be used by people with the appropriate training.

• Check the active ingredient is still authorised. Glyphosate, the ingredient in many path and patio weedkillers, is currently authorised in Great Britain, but its approval is under renewal review by the HSE, so check the label and the HSE garden database rather than relying on an old bottle.

• Spot treat. Aim a narrow spray at the weeds in the cracks, not the whole drive. Treatment works best while weeds are actively growing, usually spring to late summer.

• Never pour leftovers down a drain, sink or toilet. Rain runs off driveways into drains too, so do not spray before heavy rain.

Home-made weed killers: salt, vinegar and bleach mixtures are popular online. The HSE warns that using household chemicals as weedkillers is not without risk and is not always legal. We would not use them on a drive.

The best weed killer approach for each surface

Resin bound

Weeds do not grow through a properly laid resin bound drive, because every stone is bound in resin and there are no joints. What you see is seedlings rooting in dirt on the surface or creeping in at the edges. Brush them off and sweep regularly. Avoid harsh chemicals and solvents on resin, and on a permeable resin drive skip weedkiller altogether, as the government's permeable paving guidance advises; a gentle wash is all it needs. On a permeable resin drive, keeping the surface clean also keeps it draining, which is covered in our post on the permeable driveway.

Tarmac

Weeds on tarmac usually grow along the edges or through cracks. Clear them with a knife and brush. If you use a weedkiller, choose one labelled for hard surfaces and avoid anything solvent or oil based: fuel and solvents dissolve the bitumen that binds tarmac and leave soft, crumbling patches. Weeds pushing up through the middle of a tarmac drive are a sign of a thin layer laid without a proper base, and they will keep coming back.

Pattern imprinted concrete and exposed aggregate

A concrete slab has no sand-filled joints for weeds to root in. Weeds appear at the edges, in the narrow saw-cut movement joints, or in debris on the surface. A brush and a wash deal with most of it.

Block paving and gravel

These are the surfaces that suffer most, because the joints and loose stone give weeds a permanent home. Re-sanding joints and hoeing gravel on a dry day helps, but it is ongoing work.

Surfaces that stop weeds for good

If you are tired of weeding, the long-term answer is a jointless surface on a proper base. Resin bound, tarmac and pattern imprinted concrete have no sand-filled joints for weeds to grow through, and all of them only collect weeds where debris is left to build up. Underneath, a compacted sub-base and a membrane over soft ground stop growth coming up from below, and firmly bedded edging stops roots creeping in from the side.

That is how we build every drive: dug out properly, with a compacted base and fixed edges. Of the surfaces we lay, resin driveways in Wolverhampton are the easiest to keep weed-free, because there is nothing to re-sand, reseal or weed. On a sloping drive, the same rules apply, and our steep driveway ideas show how to keep debris from collecting at the bottom.

Driveway weed questions, answered

Will a pressure washer get rid of weeds?

It clears moss and surface growth, but it can blast sand out of joints on block paving, giving weeds more room. On resin, use a low-pressure setting.

When is the best time to treat driveway weeds?

When they are actively growing, usually between spring and late summer, on a dry, still day so the spray stays where it is aimed.

Do weeds mean my drive needs replacing?

Not if they are at the edges or in surface dirt. If they are coming up through cracks across the drive, the base is usually the problem, and it is worth getting it looked at before the cracks spread.