Published: 10.07.2026 · Motohill team · Updated: 24.10.2026
A flail mower and a grass mulcher are, in practice, the same machine. A horizontal shaft with swinging blades (flails) cuts tall grass, weeds and young scrub and immediately shreds it into fine mulch that you do not need to rake up. Choosing one comes down to a single question: what will power it. For a garden plot or orchard, a walk-behind mulcher with its own engine is enough; for meadows, a tow-behind model pulled by an ATV; on a farm, a PTO-driven mower on the tractor; and for ditches and banks, a hydraulic mulcher on an excavator arm. Below we explain how a flail mower works, and the table lists each type with real models.
How does a flail mower work?
The heart of the machine is a horizontal shaft carrying steel flails shaped like a Y or like hammers. The shaft spins fast, centrifugal force swings the flails outwards and they strike the plants. Grass and stems are cut several times before they fall, so instead of a swath you get fine material. It dries quickly, breaks down and feeds the soil.
Swinging flails have one more advantage: when they hit a stone or a stump, they fold back instead of breaking like a rigid blade. That is why a mulcher copes with waist-high grass, nettles, neglected land, field margins and orchards, where an ordinary lawn mower clogs.
Is a flail mower the same as a mulcher?
Yes. The name "grass mulcher" describes the result: mulching, which means shredding the cut material and leaving it in place. The name "flail mower" describes the design: cutting with flails. A different machine is the rotary or disc mower. It cuts with blades on a disc and leaves the grass whole, which is useful when you make hay. If you simply want to keep land tidy without raking, a mulcher is more convenient.
Types of flail mowers: comparison table
First decide what you have to work with: your own hands, an ATV, a tractor or an excavator. That immediately narrows the choice to one group.
| Type | Drive and mounting | Example models | Working width | Best for |
|---|---|---|---|---|
| Walk-behind mulcher | own petrol engine, wheel drive | Grünwelt GWX460, GWX700 / GWX700E, WEIMA WMX663, Jansen HSM-60 | 45–70 cm | plots, orchards, margins, rough ground |
| For ATV and quad | own 15 or 23 hp engine, ball hitch | Jansen AT-120, AT-145 | 115 / 140 cm | meadows, pasture, large plots |
| Rear tractor-mounted | three-point hitch Cat. I/II, PTO 540 rpm | Jansen EFG-105, EFG-125, EFGC and EFGCH series | 105 to approx. 230 cm | farms, orchards, meadows; tractor from approx. 15 hp |
| For ditches and banks | Cat. II hitch, PTO, hydraulic offset and tilt | Jansen AGF-140 to AGF-240 | 138–239 cm | ditches, verges, slopes; tractor from 40 hp |
| Front loader-mounted | Euro mount, 15 hp engine or hydraulic drive | Jansen BMM-130, HMM-130, HMM-170 | 130–170 cm | mowing ahead of the tractor |
| For excavators | excavator arm, hydraulic motor | Jansen BM-120 | approx. 113 cm | ditches, banks, scrub; 6–8 t excavator |
Walk-behind mulcher: for plots and orchards
A self-propelled machine with a petrol engine and wheel drive that you guide by the handlebars. A width of 45–60 cm lets you pass between trees and along fences, while 70 cm speeds up work on open ground. Options include the Grünwelt GWX460 (450 mm, 7 hp, 2 forward gears and reverse), the Grünwelt GWX700 and GWX700E (700 mm, 11 hp, the E version with electric start), the WEIMA WMX663 (700 mm, 9 hp) and the Jansen HSM-60 (600 mm, 8 hp Loncin engine). All models with a comparison are in the grass mulchers section.
Flail mower for an ATV or quad
The Jansen AT-120 (115 cm, 15 hp engine) and AT-145 (140 cm, 23 hp engine) have their own petrol engine with electric start and a ball hitch. The quad, ATV, garden tractor or 4x4 only pulls the mower, so no PTO or hydraulics are needed. It is a practical choice for meadows, pasture and large plots. More about the smaller model: Jansen AT-120.
Flail mower for a tractor
Mounted on the three-point hitch (Cat. I or II) and driven by the PTO at 540 rpm. The light Jansen EFG-105 and EFG-125 already work with a tractor from approx. 15 hp. The wider EFGC series (with a lifting hood for easier blade changes) and EFGCH series (with hydraulic side shift as well) need from approx. 20–30 hp up to 50 hp, depending on width. The working width should match the tractor's wheel track or be slightly wider, so the wheels do not flatten uncut grass.
Hydraulic flail mower: for excavators, loaders and slopes
Driven by oil from the carrier's hydraulic system. The Jansen BM-120 fits the arm of a 6–8 t excavator with an oil flow of 60–100 l/min. It reaches ditches, banks and scrub, cutting twigs up to approx. 3–4 cm. For a front loader with a Euro mount there are the HMM-130 and HMM-170 with hydraulic drive, or the BMM-130 with its own 15 hp engine for tractors without hydraulics on the loader. For ditches and verges behind a tractor, the AGF series offers offset and tilt and needs two hydraulic circuits.
How to choose a flail mower: 5 criteria
- Carrier and its power. Tractor power or excavator oil flow must meet the machine's requirements. An underpowered carrier works at its limit and wears faster.
- Working width. A wider machine means fewer passes but needs more power and room to turn. For narrow orchard rows a narrower model is better.
- Type of vegetation. Any mulcher handles grass. Dense weeds, reeds and regrowth need spare power, for example 9–11 hp in a walk-behind machine instead of 7 hp.
- Terrain. For ditches and slopes choose side shift, a bank mower or an excavator arm. For level meadows a tractor or ATV mower is enough.
- Ease of use. Reverse gear, electric start and a lifting hood for flail changes save time over many seasons.
Safe operation and common mistakes
Before mowing, walk the area and remove stones, wire and thick branches: the flails run at high speed and can throw them. Do not set the cutting height too low, or the blades will dig into the soil. Drive more slowly in dense growth, because going too fast overloads the gearbox and belts. After the season, check belt tension, flail play and gearbox oil. Do not mulch thick branches; a wood chipper is the right tool for them.
Jansen machines are delivered in a crate, partly disassembled, and are assembled by the customer. Before the first start, check and top up the gearbox oil, and on engine-powered models the engine oil too.
Frequently asked questions
Can a flail mower handle tall grass and bushes?
Yes, that is its main job. It cuts waist-high grass, weeds and thin shrub regrowth. Thick branches need a wood chipper.
How is a flail mower different from a rotary mower?
A rotary mower cuts with blades on a disc and leaves the grass whole, for example for hay. A flail mower shreds the material straight away, so there is nothing to collect.
Do I need to rake the grass after mulching?
No. The shredded material stays in place, breaks down quickly and acts as a natural fertiliser.
Which flail mower is right for an ATV?
A model with its own engine and a ball hitch, such as the Jansen AT-120 (115 cm, 15 hp) or AT-145 (140 cm, 23 hp). The ATV only pulls the machine and needs no PTO.
Is there a flail mower for a mini excavator?
The Jansen BM-120 is designed for 6–8 t excavators with an oil flow of 60–100 l/min. Before buying, check your machine's weight and hydraulic flow in its documentation. If in doubt, call us and we will compare the figures together.
Need advice?
You will find walk-behind models in the grass mulchers section and machines for tractors, ATVs and excavators in the flail mowers category. If a two-wheel tractor will do the mowing, read our guide how to choose a two-wheel tractor. Questions about a specific model? Call +48 780 140 444; we speak Polish, Ukrainian and Russian. We ship by courier across Poland, delivery to other EU countries is possible with cost and timing confirmed when you order. 24-month warranty, 14-day returns.