Green gardens: How low should you mow your lawn?

The wildflowers we see in the wider countryside can be in the soil in our own gardens, ready to emerge with a little managed 'neglect' in areas of the lawn. Picture: iStock

I'll admit it. I’m a bit obsessive about mowing, and now I can use the battery mower to slice and dice whenever I feel like it with power straight from the roof — the maniacal behaviour has gotten worse. I executed the knee-deep stuff with the feted “first cut” in March.

The uncomfortable truth is that cutting the grass to the sod in our swiftly approaching summer is terrible for the native wildlife struggling around our gardens. 

The Royal Society for the Protection of Birds (RSPB) offers this advice simply taking into consideration our feathered friends: “Having a large garden allows you to grow areas of long grass. Growing it against a shrub border will buffer the wind. This increases humidity within the shrubbery and improves conditions for invertebrates — an important food for birds and mammals. 

A wildflower meadow on the Ring of Kerry. Picture: iStock

"It also provides habitat for insects eaten by birds and mammals, as well as an additional source of seed. Manage your lawn at a height of 3.5cm to 5cm until late May. If it is a particularly wet season, you may want to continue cutting for a little longer, then allow the grass to grow throughout the summer.”

CLIMATE & SUSTAINABILITY HUB

The RSPB advises that grass cutting should ease over summer and only be started again in late September, which is right when I’m struggling at the highest range of the blades through increasingly wet grass. What’s a girl to do? If I adhered to that, I would have to strim first before tangling the mower in the silage.

Out in the fields is one thing, on the civilized approach — I’m a weak product of years of suburban lawn lore. Any change is going to take some serious commitment, turning a blind eye to my expectations of what is “neat” and acceptable for a grown-up garden. I could leave large fluffy swathes around the edges of my lawn — why not?

Combining shorter and longer meadow styles is ideal. Picture: iStock

According to the Irish Wildlife Trust a super short lawn is a “wasteland” for pollinating insects. Balancing that, the bald, hard reality is that wilding the garden is brilliant for bees and harder for humans at least at first (iwt.ie). We have to get our 21st-century heads around the whole principle of don’t mow/let it grow. Imagine an area of your garden enriched with Irish classics like sweet vernal grass, red clover, meadow buttercups and more. It takes putting your heart right over your head.

Many environmentalists advocate for cutting grass only every four-six weeks year-round and letting the fertility of the ground reduce dramatically over time. This allows scrappier native flowers and plants to emerge over greedier pernicious weeds (thistles, nettles, docks). These shoulder their way out of an artificially fertilised, emerald lawn and tolerate being beheaded weekly or drenched in commercial spot-on weed killers that, leaching into the earth, do even more environmental damage.

These wildflowers show off their summer colours in Skibbereen, West Corl. Picture Dan Linehan

We want to be seen to manage our gardens, being as scintillatingly tidy as our pert, respectable neighbours. When your grass is long, people in built-up areas do talk. In the United States, the local community Beautification Officer will send you a tersely worded note. 

Our National Biodiversity Data Centre, in their 2019 report on the launch of the Pollinator Plan, said it loud and clear. “The trailblazers took to this straight away – they’re the people who don’t care what anyone thinks. To the rest, even if it’s understood how valuable an action it is, deciding to let your lawn grow can make us mildly uncomfortable.” The report describes the golf course velvet of a domestic lawn as comparable to a post-apocalyptic landscape for human beings.

WORK OF ART

No matter the situation or what size your lawn might be, there’s plenty of room for effort and compromise. Mown paths are sylvan and pretty in a larger garden, where you can get the grass to turn to waving meadow during the summertime. A natural work of art, once established, this precious environment will help invertebrates, butterflies and bees to thrive, kicking up some of their number to the birds feeding their youngsters.

Mown pathways can be used to access parts of the garden rewilded back to our native wildlife.

Don’t expect a lush carpeting of flowers — a good scattering of what we see as blossom hides a layered, deeply nutritious story in the five eyes of a bee.

Some gardeners stitch in blossoms by broadcasting other varieties by the packet or box. This can look slightly artificial, but it shows the spirit is willing.

There’s generally no need to introduce plants, as chances are, there is a wide variety already there in seeds and pods, previously whipped down by the mower. 

Where you do make mown paths, try altering their direction occasionally to allow the ground to recover from the directed foot traffic. 

It may take a few seasons for the meadow to look really good. Anyone who has watched the wilding of the surrounds of their local Lidl or local authority land will remember how bleak the area looked that first year or two.

In a smaller garden, we can have a go at not simply tall waving hay, but short flowering meadow-land which will appear with some well-considered neglect, and that four-six-week mow on the highest setting.

Combining shorter and longer meadow styles is ideal, and you can find advice on nurturing varying heights of plants all over the re-wilding community online. Scythes have even returned to the gardening scene, a gentle swoop to top hay-height grasses, replacing the indiscriminate, ground-level swipe of the strimmer. Careful, now.

In the case of the shorter meadow, the IWT says that any cut grass should be taken away rather than being mulched into the ground (where the dead grass would impede growth). 

Another idea I’m taking on board is to allow less prominent areas of the garden to return to nature with a little topping every few weeks, pulling out more thuggish weeds like docks where needed. The area close to a compost heap or behind a shed could be ideal, and the long grass will hold moisture during the driest weeks. With calendula, violets and bluebells currently jewelling the banks despite every cruel cut I’ve made, my mind is made up for summer 2023 and beyond.