I have recently bought a bypass lopper and apparently there is a correct way to position the blade when cutting; that is, reversing the position would damage the branch.

gardenmyths.com claims:

fuf.net makes the same claim:


Apparently, one side of the branch gets crushed when cutting. Is there any truth to any of this?

In the gardenmyths image, it seems more likely to me that the blade side would get crushed, because the "hook" side has less going on during the cut.

Can anyone confirm or deny this? Is there any convincing argument to any of this?

  • 1
    The blade side is CUT. The force to cut is generated by the hook side - which crushes the bark. It's quite obvious if you look at both parts after cutting. If the blade side is crushed, the blade is dull and needs to be sharpened. – Ecnerwal Mar 11 '17 at 19:07

Absolutely TRUE! That blade needs to be closest to the living tissue to cut cleanly or the other side of the bypass crushes the living tissue allowing bacteria, etc. to enter the system. Bypass pruners are the only pruners that should be used. Anvil pruners do the exact same crushing. Bypass pruners with sterilized SHARPENED blades cut surgically. Cleanly. Always use alcohol in between different plants you are pruning. I mean use the alcohol to clean your blades, not take sips of your favorite beverage...grins!1


If using an anvil pruner in addition to crushing by the anvil, using the anvil on the discard side enables cuts to be made much closer to the branch collar (NB: do not cut into the collar itself). This enables the cut to heal over better (stubs that are left will die back into the main stem leading to a bigger scar and potentially introducing disease).

In general, anvil pruners are better for cutting harder materials than bypass. This is because both blades are thin on a bypass cutter and can twist, bend or splay apart resulting in a poor cut. In anvil pruners, the anvil adds rigidity and helps stabilise the tool during the cut. They are more widely used in commercial horticulture than bypass. Bypass are good for thinner, softer materials. Commercially, they find their greatest use in the cut flower industry where neither side of the cut can be crushed. Correctly maintained and used, the blade side of a cut from an anvil will be indistinguishable from the those of a bypass pruner. A serious horticulturalist will have a range of pruners so they can select a tool appropriate for the job.

  • Yes, I also thought that the twisting that occurs with a bypass lopper during the cut must cause damage to the branch. Sometimes is not as black and white. – Tahir Hassan Mar 13 '17 at 12:33

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