Standing in front of a range of weedkillers, the question seems simple, yet it regularly leads to a costly purchasing mistake. Do you need a selective Garlon GS, or a total glyphosate weedkiller? The answer depends neither on the price nor the brand, but on one decisive factor: what borders the area you want to treat. Here is how to make the right choice confidently, including the mixed situations that often complicate the decision.
The factor that determines everything: what surrounds the area to be treated
Before comparing products, you first need to answer one question, and only one: does the area you are going to treat touch a plant that you want to keep alive?
A total glyphosate weedkiller makes no distinction. It destroys every green plant touched by the spray, without exception. That is precisely what makes it the most effective tool for clearing an entire surface, and also what makes it unsuitable whenever a plant that needs to be preserved is within range.
A selective weedkiller such as Garlon GS works in the opposite way. Its fluroxypyr formulation targets broadleaf weeds, brambles, nettles, thistles and bindweed, while sparing the grasses in your lawn. This selectivity is not an option that can be switched on or off; it is built into the product's mode of action.
The question to ask is therefore never "which product is strongest", but "what could I damage if I make the wrong choice". A shared hedge, a perennial bed or an established lawn: each of these immediately shifts the choice in favour of a selective product, regardless of how difficult the vegetation to be removed may be.
When a selective product is the obvious choice
Three situations make choosing Garlon GS almost automatic, because the risk associated with a total weedkiller becomes disproportionate.
A lawn you want to keep, overrun with brambles, nettles or thistles. This is the most obvious use case for a selective product: treat the unwanted plants without having to reseed afterwards. A total weedkiller applied here would destroy the lawn along with its target, turning a simple weeding job into a complete lawn renovation project.
A hedge or shrub bed immediately bordering the area to be treated. The slightest drift of a total product onto these ornamental plants can cause visible decline several weeks later, long after the application has been forgotten. A selective product greatly reduces this risk, without eliminating it entirely, so careful spraying is still essential.
An area combining lawn and flower borders, such as a grassed bank at the base of a fence. As soon as the area to be treated itself contains elements to preserve, intermingled with the unwanted vegetation, a selective product remains the only option that does not require extreme precision during application.
When glyphosate remains more suitable despite nearby plants
The mere presence of a nearby plant does not automatically make a selective product the right choice. Three situations still favour a total weedkiller, even when there appear to be constraints.
A completely hard-surfaced area, such as a gravel path, paved courtyard or patio, where no vegetation is meant to grow. Even if this area adjoins a flower bed, the distance and careful application with a lance sprayer are generally enough to make treatment safe, while a total product remains unbeatable in terms of its range of action, including on invasive grasses that a selective product does not affect.
An overgrown area to prepare before cultivation or planting. The aim here is not to preserve existing vegetation but to start again with bare soil. Glyphosate, which destroys all vegetation, including the roots, corresponds exactly to this objective, whereas a selective product would leave the wild grasses in place.
An infestation of couch grass or other unwanted grasses. This is a frequently misunderstood point: Garlon GS acts only on broadleaf weeds; by design, it has no effect on invasive grasses, which belong to the same botanical family as the lawn grass it is intended to spare. For this type of weed, only a total weedkiller provides an answer, which sometimes means accepting the temporary loss of a lawn in order to restore it afterwards.
The mixed-area situation: one part to preserve, another to clear
This is the most common situation in practice, and the one that causes the most hesitation, even though the answer is actually quite simple once the principle is understood.
Never look for a single product to treat everything at once. This is the reflex that most often leads to a mistake: either a total product damages what should not have been touched, or a selective product leaves untouched the hard-surfaced area overrun with grasses that it cannot eliminate.
Mentally divide your garden into two distinct areas, and treat each one with the appropriate product. A typical garden often combines a lawn to preserve, where Garlon GS is the right choice for the broadleaf weeds invading it, and a path or courtyard to clear completely, where glyphosate remains the most effective option.
Clearly mark the boundary between the two areas before starting, using a simple visual marker, a stake, a temporary sheet or simply careful observation of the ground. This boundary, more than the choice of product itself, prevents application errors along the edges between the two treatments.
Treat the two areas in separate sessions rather than one immediately after the other, thoroughly cleaning the equipment between them to prevent residue from one product contaminating the next application.
How to apply the chosen product effectively, whether selective or total
Whatever product you choose after this assessment, the application method follows shared principles that determine the result.
Treat actively growing vegetation, with well-developed foliage, never vegetation dried out by drought or slowed by cold weather. This is the condition that ensures effective absorption, regardless of the product's mode of action.
Choose a period of stable weather, with no rain forecast in the hours following application, and dry foliage at the time of spraying.
In boundary areas between selective and total treatments, or near a sensitive plant, a protective hood fitted over the nozzle greatly limits the risk of drift, whatever product is used.
Difference between selective and total weedkillers: the mode of action in one sentence
To put an end to any confusion, here is the distinction that sums up the entire article.
Glyphosate blocks a function shared by almost all green plants, which explains its total and indiscriminate action. Fluroxypyr imitates a growth hormone to which only broadleaf plants remain durably sensitive; grasses manage to break down the molecule before it can act, which explains its selectivity. This difference in mechanism, not the brand or the price, should guide your choice. We explain how this works in detail in our article on the mode of action of fluroxypyr.
Garlon GS or glyphosate: what to remember
In summary, the choice between Garlon GS and glyphosate is never about the product's strength, but about what surrounds the area to be treated. Whenever a lawn, hedge or shrub bed needs to be preserved, a selective product is almost automatically the right choice. On a completely hard-surfaced area, an overgrown plot to prepare, or in the face of an infestation of unwanted grasses, glyphosate remains the most suitable option despite any nearby constraints. On a mixed site, never look for a single product: divide the area, treat each part with the appropriate tool, and clearly mark the boundary between the two before starting. It is this reading of the site, well before comparing the products themselves, that prevents most purchasing and application errors.
