Yes...sadly. At least here in my UK gardens. Have had to either redig and clean out the beds or ignore the nasty whiff and keep cutting back - unlike real grass, it does eventually weaken a bit as it cannot tiller from the base). I think cardboard covering and mulching can help but I never have enough clear area to do much of that

Rosaprimula, I can tell you that onion grass even comes up through cardboard!

Recalcitrant weeds - our nemesis hey...and there's always something. My horror weed this year (apart from the hateful bindweed and couch grass) is the virulent herb bennet - geum urbanum. Solidly covers every inch it lands on and has an annoying habit of growing tight up against my perennials in impenetrable sheets of foliage. Have even pondered the possibility of using them as a living mulch, strimming any developing flower heads. At any rate, here we are, weed season ramping up (my starting point is always the emergence of the bindweeds...of which I have both ubiquitous varieties). Another season either on my knees or endlessly bending over to pull a bazillion sodding nuisance plants.

Could be worse, I suppose. I don't have marestail, knotweed or a trillion mallows.

Onion grass? Like wild onion, the edible? I look forward to the spring harvests of it. There are spots in the yard I mow around till it goes to seed and I harvest and spread that around too. Other spots just get mowed when it's time there. Or is the onion grass something else?