crittergarden said:Interesting.
I have had euphorbia myrsinites, Euphorbia dulcis 'Chameleon', and Euphorbia polychroma 'Bonfire', all of which came to me from other gardeners and DO seed around, but not in an uncontrollable way.
I'm really interested to see which one this one might be.
It is what Kent said, unquestionably -
Euphorbia cyparissias. It is none of the ones you mention.
The source of its (
Euphorbia cyparissias, that is) invasiveness is thin, thready rhizomes that are very difficult to control, since they're fragile. It also seeds very successfully, with seeds being cast some distance from the parent plant (as in many other
Euphorbia).