Steep slope mowing options in NZ, from ride-on to remote control

Mowing is grass. Rank pasture, kikuyu, long grass on a reserve bank, a dam wall, a roadside batter that has got away. If the growth is woody, gorse, blackberry, scrub, saplings, it is not a mowing job however steep or flat it is. That is mulching, a different head on a different day.

The distinction matters because the tools are different. A flail mower gives a clean, even, striped finish on soft growth. Put it into mature gorse and it will stall, damage the head or leave a mess. This guide is about grass.

Most ride-on manufacturers rate their machines to around 15 degrees, and some say less. The practical limit is when the machine starts to slide sideways or the front lifts on the climb. Ride-on rollovers are a common cause of serious injury on lifestyle blocks precisely because the bank at the back looks manageable from the seat.

Wet grass, a dip you did not see, and a turn across the slope are the three things that put a ride-on on its side. If you are already nervous doing it, that is the correct instinct.

A tractor with a topper or a proper slope mower handles more than a ride-on, and a low, wide, ballasted tractor with a competent operator can work to around 20 to 25 degrees on dry ground. Tractor rollovers remain among the most serious causes of death and injury on New Zealand farms, and most of them happen on slopes the operator had worked before.

There are winch-assisted and tethered tractor set-ups that push the limit higher on some terrain, mostly in forestry. For a farm bank or a council reserve they are rarely practical.

A brush cutter or scrub bar works on any slope a person can stand on, which is why it is the default for the awkward bits. The costs are time and safety. A person clears a few hundred square metres of long grass in a day, and steep, uneven, wet ground under long grass is where ankles and knees go. It is fine for a small patch. It does not scale to a bank that is measured in hectares.

A remote-controlled flail mower is a tracked machine with no cab. The operator stands on stable ground with a clear view and works the machine on the bank. Because there is nobody on it, the slope limit is set by traction and machine stability rather than by whether the operator survives a roll, which is how the working limit can be as high as 55 degrees. Degrees, not per cent.

GRazer's compact machine, Connie, carries the flail head and gets in from 1.4 metres. She is the machine for reserve banks, stormwater basins, dam walls, roadside batters, kikuyu slopes and the long grass on the bank behind the house. The finish is clean and even, the kind you would expect from a tractor mower on the flat, on ground a tractor should never be on.

The usual pattern is a regular programme rather than a one-off: a slope that is mown on a schedule stays a slope you can see, rather than one that quietly turns into gorse.