If a soft, pale green moss has crept through your lawn on heavy, damp soil, the odds are good that this is the one. Pointed spear-moss is among the most abundant mosses of wet grassland across Britain and much of Europe, and it owes its name to a small, distinctive habit: the growing tip of each shoot is drawn out into a hard, sharp point, like the head of a tiny spear or the tip of a fine brush.
Recognising the spear
The tell is right there in the name. At the end of every shoot the youngest leaves fold tightly together around the growing point instead of spreading, tapering the tip into a stiff, pale spearhead a couple of millimetres long. Rub a shoot between finger and thumb and that point feels firm and slightly prickly, unlike the soft, open sprays behind it. The plant is a creeper, sending irregularly branched stems through the turf in loose wefts rather than building tight domes, and its colour runs from a fresh yellow-green to a paler, almost whitish green, often with the main stems flushed a dull red where the light reaches them. The leaves themselves are small, oval and concave, and carry no midrib worth the name, so held to the light a leaf shows an even, unlined green.
Where it grows
Damp and a touch of lime are what it asks for. Pointed spear-moss thrives on neutral to base-rich ground that stays reliably moist: fens and marshes, dune slacks, flushed hillsides, the wet margins of ditches and ponds, and, above all, the sort of poorly drained lawn or meadow that squelches underfoot in winter. It is far less fussy about mowing and trampling than most, which is why it holds on in gardens where finer mosses give way, and it can sheet over bare damp soil quickly once it takes hold. Capsules, curved and cylindrical on a red stalk, appear only now and then, so most of its spread is done vegetatively, whole shoots rooting afresh from broken fragments.
What its arrival tells you
A moss like this is worth reading as a symptom rather than just a nuisance. Where it carpets a lawn it is reporting on the ground beneath: shade, compaction and, most of all, water that lingers because the soil drains badly. Grass grows thin and sulky in exactly those conditions, and the moss simply occupies the gaps the turf can no longer fill. So its spread is less a cause of a struggling lawn than a consequence of one, and the same reading holds for the wider question of moss in lawns generally.
Keeping it, or clearing it
Whether you fight it depends on what you want from the ground. For a soft, low, green surface in a shaded and naturally damp garden, this moss makes a perfectly pleasant carpet that stays green through drought and needs no mowing, an approach set out in full under making a moss lawn. If instead you are set on grass, scratching the moss out with a spring-tine rake only ever buys a season, because the damp, shaded conditions that invited it are untouched. Lasting control means mending the ground itself: easing compaction by aeration, opening up overhanging shade, and improving drainage so the surface dries between downpours. The general campaign, and the limits of the iron-sulphate treatments sold for the job, are covered under getting rid of moss.
A creeper among the cushions
Because it spreads in trailing, branched wefts rather than upright tufts, pointed spear-moss sits firmly among the pleurocarpous mosses, the carpet-formers set against the cushion-builders in acrocarpous and pleurocarpous mosses. Once the spear-tipped shoots have caught your eye you will notice it everywhere the ground runs wet, and a hand lens turned on those pale points shows one of the neater pieces of design among the common mosses, a plant that has made a virtue of the damp, trodden corners most others cannot abide.