this kind of plant protect moister and grass weeds well while vegies continue growing. it very easy to remove them off when i ready to harvest vegies, just cut to square by scissor.
https://tropical.theferns.info/viewtropical.php?id=Portulaca quadrifida this kind of grass is easy to remove because of the shallow root system.
I havent come across this one yet, not sure its here in NZ. Good luck with it and let us know how this works out!!!!!
there are different genus in NZ. may be chickweed look closer. here are some of potulaga in NZ. good luck mischiff, have a nice days ever https://naturewatch.org.nz/taxa/58991-Portulaca-oleracea