I used to live not far from an osier bed where each year all the willow
branches were cut away close to the ground. The whips were used for
basketry and fencing.
Now, February, is the ideal time to pollard your willow. Saw each branch
down as near to the ground as you think fit. Often the nearer to the ground
you cut a branch, the more new young whips you will get growing from the
stump.

MikeCT
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"Emery Davis" Asked:

I have a variegated willow shrub (don't have the exact name but I
suspect it is Salix integra 'Hakuro Nishiki') which is getting a little
large for its spot. It has a well structured form, so I thought it would
do well pollarded.

How to begin? Just saw a branch at the desired height? My RHS pruning
guide is a little vague about starting, the picture looks as though the
cut was made where desired and then whips came out, but it's not clear.

Thanks for any advice,