Ground elder (Aegopodium podagraria) is a pernicious weed, which spreads quickly via a network of rhizomes underground.
An unwelcome discovery
Shortly after we moved into Neats Home Garden, my mother-in-law informed me that we 'had ground elder.' I soon realised that all the beds were infested with it, and that it was entangled in the main roots of many plants, making it incredibly difficult to split and lift them without spreading it even further.
I realised that I had to tackle the ground elder before I could start replanting. Initially Mr. P persuaded me to use Roundup, which we did twice. However I was very reluctant to use it. I noticed that in other areas, where Mr. P used it to reduce the nettles, the ground looked like it had been napalmed. Moreover, to get rid of the nettles permanently, I still had to dig down and remove the roots after it had died back.
... or labour?
So I abandoned chemicals in preference for old-fashioned labour. Hand-weeding, several times a season, has reduced the infestation to a lurking presence. Introducing other ground-cover plants, like Lamium maculatum 'White Nancy,' Origanum marjorana, and hardy geraniums, has also helped, since they fight the ground elder by spreading themselves. We have also applied a thick mulch of bark chippings twice a year to weaken the weed's root structure, and I do think this has helped, even if opinion is divided on its aesthetic appeal.
We will never 'get rid' of the ground elder- the only way to do that would be to dig out the soil and plants, and start afresh with sterile compost. But we are now able to keep it at bay with some regular weeding without resorting to napalm.