Chelidonium majus perhaps?

i suspect Chelidonium majus.
often confused with the native Stylophorum diphyllum.

(non native) Chelidonium majus buds:
{{gwi:188008}}

(the native) Stylophorum diphyllum buds
{{gwi:188011}}

Hmmmm, certainly is one of those two! Curiously, I actually HAVE a Stylophorum diphyllum which I got at a plant swap a year or two ago. But I planted it on the other side of the yard, in a wooded glen (I am going out right now to compare the two!)

Is there a definitive way to tell the two apart at this stage of growth (before they've bloomed but while they are in bud)? I'm guessing it's far more likely I've got a boatload of the non-native (and undoubtedly invasive?) Chelidonium majus, but wouldn't it be wonderful if that boatload was of the natives instead!

Aha! Proof is in the pudding (or in this case, the leaves). On the right is the Stylophorum diphyllum, from the wooded glen. On the left is a stem from one of the many plants popping up across the yard, in a "rustic" area of brambles an black raspberries (wild) on the edge of the woods. Definitely NOT Stylophorum diphyllum, so Chelidonium majus for sure. (And lots of it!)

Should I be pulling the non-native up Chelidonium majus or can I leave it?

{{gwi:188012}}