a tiny meadow full of wildflowers

Mowing and not mowing the grass is making the news in the South West of England this Summer.

Police were informed after a churchyard nature area was “accidentally” mown by contractors in Cornwall. According to the Western Morning News the mangled bodies of hedgehogs were extracted from within the innards of the contractors’ mowers. Villager Daniel Grant said the area had been “completely destroyed”. The area is normally left until Autumn before being mown. Mowing wildflowers before they have set seed is a bad thing apparently.

Meanwhile in Dorset a village has had to withdraw from entering the best kept village competition (which it has previously won) because the council had not mown the verges. Vice chair of Owermoigne Parish Council Tony Wormald complained the grass in the village was “in a terrible state”. The County Council claimed they had left the grass uncut on account of the cultivated daffodils. “To ensure a good show next spring we need to allow the green parts to produce energy which is stored in the bulb for the next year’s growth.” I wonder whether these Daffs had been planted as part of the Best Kept Village competition.

Elsewhere Dorset County Council have been trialling sowing road verges under their management with Yellow-rattle, aiming to reduce the growth of grass by more natural means using this parasitic plant, instead of having to mow them.

It seems there will always be someone who complains whether the grass is cut too short, left too long or mown at the wrong time. The truth is there is no perfect time to mow grass. Every decision to mow has to balance different and sometimes conflicting priorities. Many people do want neatly trimmed short grass without any flowers in it. Others want to see flowers which benefit bees, butterflies and other insects, as well as looking attractive.

There is also a mistaken notion that it is necessary to leave flowers until they have set seed, presumably the thinking being that flowers need to shed seed in order to appear in subsequent years. This is based on a misunderstanding of plant biology. Most flowers that occur on road verges or in churchyards are perennials. They do not need to reproduce from seed each year. Many perennial plants can also reproduce vegetatively, for example by means of runners or stolons. Plants such as ivy, bindweed, clematis and bramble all produce runners or stolons which spread either above ground or through the soil. By not mowing until Autumn, these plants are given a big competitive advantage as they can colonise new ground while other plants are stuck where they are. Other plants such as bulky competitive grasses like cock’s-foot, false-oat grass or Tall fescue do very well when mowing takes places late in the season. These can form large tussocks or spread through the sward with runners. So it is often the case that churchyards or verges that are not mown until Autumn quickly get taken over by brambles, ivy or become dominated by tall bulky grasses.

Road verges also receive a healthy dose of nitrogen fertiliser from the exhausts of passing vehicles, and those bulky competitive plants are just better at taking up that extra nitrogen than smaller flowers, so this again gives a further push towards what might be called “Rank” vegetation.

Regular mowing (and, essentially, removing the arisings) will reduce the vigour of these competitive plants, and prevent plants with runners from spreading. Removing the arisings also removes nutrients from the grassland. This is exactly what is needed for the wildflowers that most people would like to see on verges and in churchyards, to flourish. Where a verge or a churchyard has become rank or overgrown, it may need several cuts a year for the first few years before the “bullies” are under control or removed. These cuts should be earlier in the year, rather than later, because it is earlier in the year when the vigorous plants are growing at their fastest, and removing their growth at this time is most effective at weakening them. It is also necessary to create bare ground when mowing. This provides opportunities for buried seed of flowers to germinate. Yellow-rattle also needs bare ground for its seeds to germinate – best practice suggests at least 50% of an area must be bare to get successful yellow-rattle establishment.

So was the Cornish churchyard really devastated – had the wildflowers been completely destroyed? It was extraordinarily crass of the contractors to mow around the sign saying “churchyard nature area do not mow”, or some such wording. And in creating ideal conditions for hedgehogs it’s not surprising that individuals were killed when those conditions were removed. I would tentatively suggest though that all the flowers that were in the churchyard will be back again next year, perhaps in greater numbers because of the early cut (depending on whether the arisings have been removed or not.)

Nature is pretty tenacious when it comes to things like mowing. Grassland plants have all evolved to be adapted to being grazed through their growing season, and mowing is a proxy for animal grazing. Indeed grassland plants depend on some activity keeping the habitat open, and preventing succession to scrub and woodland. While mowing verges every April or May will prevent plants from flowering, overall it’s better to mow earlier (June or early July) than later (August – October); as long as flowers get a chance to flower and set seed every few years they will be fine.

Caring for God’s Acre is an excellent charity which produces a range of guidance for how to best manage churchyards.