If you have noticed small blue flowers appearing in patches across your lawn, you are almost certainly looking at speedwell. There are several species that establish themselves in Irish lawns, the most common being slender speedwell (Veronica filiformis) and germander speedwell (Veronica chamaedrys), though field speedwell turns up too, particularly on bare or recently disturbed ground. They are low-growing, they survive the mower easily, they spread steadily through the season, and they produce a flower that is, by any honest measure, rather beautiful. The instinct for many gardeners is to treat them as a problem. I would ask you to pause before acting on that instinct, because the question of what to do about speedwell in an Irish lawn is worth thinking through properly.
Which speedwell is in your lawn?
Slender speedwell
Veronica filiformis. The most frequent in closely mown lawns. A creeping mat of small rounded leaves with pale blue flowers from spring into early summer. It roots at the nodes as it spreads, which is why it forms defined patches rather than appearing evenly across the lawn.
Germander speedwell
Veronica chamaedrys. Slightly more upright, with a deeper sky-blue flower and two rows of fine hairs running down opposite sides of the stem.
Both are perennials, and once established they are not going anywhere without deliberate intervention. Slender speedwell is not native: it was introduced as a garden plant and has naturalised widely. Germander speedwell is a native wildflower. Both provide a useful early nectar source for bees and other pollinators at a time of year when garden flowers are still sparse.
A lawn with speedwell in it is not a failing lawn. It is a lawn that has found a low-growing companion plant willing to fill the spaces where grass is thin. The presence of speedwell is worth reading as information rather than treating as an affront.
What speedwell is telling you about your lawn
The reason speedwell takes hold where it does tells you something useful about those parts of your lawn. It favours areas where the grass sward is thin, where the soil is slightly compacted or low in fertility, or where shade has weakened the grass enough to create gaps it can exploit. A dense, well-fed lawn growing in reasonable soil is actually quite good at competing with speedwell and keeping it in check.
So if you have significant patches appearing, the most honest response is to ask what those patches are telling you about the grass, rather than simply trying to suppress the speedwell itself. Improving drainage, relieving compaction with a garden fork, overseeding thin areas in autumn, and feeding the lawn properly through the growing season will all do more lasting good than any attempt to eliminate speedwell directly. Address the conditions and the grass will gradually outcompete it on its own terms.
The soil beneath the lawn
The soil beneath the lawn matters here as much as the grass above it. A lawn sitting on compacted, biologically depleted or poorly structured ground will always struggle to maintain the dense sward that keeps opportunist plants at bay. Improving the soil is the most direct way to improve the lawn. If speedwell is appearing across a significant area, that is a signal worth responding to at soil level rather than surface level, and the results are better and longer-lasting than anything that comes from a spray. Garden soil in Ireland explains what to look for.
Thicken the grass from the soil up
NutriChar is a certified organic biochar plant food, made using a patented process that locks nutrients into the biochar structure so they stay in the root zone rather than washing away in Irish rain. Spread across the lawn and over freshly overseeded patches, it feeds the grass steadily and improves the soil's structure and biology, so the sward thickens and leaves speedwell less room to spread.
What do you want your lawn to be?
The broader question behind all of this is what you actually want your lawn to be. The idea of a pure grass sward, uninterrupted by any other plant, is a relatively recent and heavily marketed ideal. It requires consistent chemical input, significant ongoing effort and plenty of cost. An Irish lawn with clover, self-heal, speedwell and the occasional daisy in it is not a neglected lawn. It is a lawn that is doing something useful for the insects and birds that depend on your garden as well as looking after itself.
The two things are not in conflict. You can have a lawn that is tidy, well kept, clearly managed, and still contains a range of low-growing plants that add colour and support wildlife. Most people who look at a lawn with speedwell in flower are not thinking it looks unkempt. They are thinking it looks like a garden that is alive.
Reducing speedwell without weedkiller
If you have decided you genuinely cannot accept the speedwell and want it reduced, I do not use or recommend weedkiller of any kind, selective or otherwise. The damage that herbicides do to soil biology, to pollinators and to the wider ecology of a garden is not a trade-off I am willing to make for the sake of a uniform sward.
- Small patches: lift them by hand with a trowel or hand fork, working carefully to take out the rooted stems rather than tearing off the top growth. Rake the soil lightly and overseed straight away, because bare ground is exactly what speedwell uses to re-establish.
- Larger areas: there is no quick fix. Raise the mowing height slightly, overseed in September and improve the underlying fertility of the soil. It is a slower process, but it is the one that actually works without cost to the garden around it.
For mowing height and timing, see the first grass cut of the year, and if moss is filling the same thin areas, moss on my lawn.
Speedwell questions
What are the small blue flowers in my lawn?
Almost certainly speedwell. Slender speedwell (Veronica filiformis) is the most common in closely mown Irish lawns, with germander speedwell (Veronica chamaedrys) and field speedwell also turning up, particularly on bare or recently disturbed ground.
Is speedwell bad for my lawn?
Not in itself. It fills the spaces where grass is thin, so it is a sign of thin grass, compaction, low fertility or shade rather than a cause of them. It also provides early nectar for bees and other pollinators.
How do I get rid of speedwell without weedkiller?
Lift small patches by hand with a trowel or hand fork, taking the rooted stems out, then rake and overseed straight away. For larger areas, raise the mowing height slightly, overseed in September and improve the soil so the grass can outcompete it.
Is speedwell good for pollinators?
Yes. It flowers from spring into early summer, providing a useful early nectar source for bees and other pollinators when garden flowers are still sparse.