Yes, I can see that "blowball" has nothing to do with clog; I was talking abut "clock", which until today I thought was the only word for a dandelion head.
I'd be surprised if that sense of "clock" came from Irish though: my local variety is not particularly influenced by Irish, or any other Celtic language. There’s a children's game that uses clocks to "tell the time" though.
English “blowball” is a compound of “blow” + “ball” (its earliest reference in the OED is from 1578), so it’s completely unrelated to clog. The blowball meaning of “clock”, however, is likelier to be a calque from Irish clog (in its older “bubble” or “cluster” meanings) or perhaps from Scottish Gaelic clag (I don’t know if it has the same range of meanings as clog has) — the earliest reference to the blowball “clock” in the OED is from 1847, without an etymological trail.
Sorry for answering late: It should be "chlog", as "mo" takes lenition. This is not only in the tips and notes, but also in GnG
Strange enough google gives almost as many Irish language hits for "mo chlog" as for "mo clog", which would that it is a relatively commonly accepted way of speach (maybe some dialect).