Rich Taylor writes:

R Can you please help. I work at a local hospice and am getting a majore
problem with oxalis taking over in the bedding schemes every year. The
only way i can see to control it is to replace all the soil in the beds
but that would be to costly to do as we are a charity and the money is
better spent on patient care.
Is anyone else had this problem and how did you sort it out. Is there
anything i can spray to control the problem..

Google for "oxalis control".

Looks like a difficult weed to control.

I think I'd go with black plastic.

Put black plastic over the bed, cut holes for a few
plants, cover the rest with wood chips.
The oxalis that doesn't reach the light should give up
in a year or 2.

Pulling and Roundup won't work.