Both Gotu Kola (Centella asiatica) and native Violet (Viola hederacea) have very similar leaves and growth habits.
Fine if the native Violet is flowering, there is no doubt.
The most obvious difference to me is that Gotu Kola in general prefers the sun where native Violet rarely grows in the sun.
A secondary difference is the Gotu Kola leaves have a different serration to the native Violet leaves. And Gotu Kola is generally a more tough leaf where the Violet's leaves are very soft.
Not exactly scientific but the best I can do. Some pix may (or may not!) make any more clarity.
Native violet LEFT; Gotu Kola RIGHT.
Gotu Kola growing in the sun.
Be careful trying things from the garden. Unless it was sold as food plant (of if you can identify it with certainty), just because it's widely available, doesn't mean it's not toxic.... For example, daffodils, and calla lily are widely available, but they're toxic. Just a few months ago, a family of four in HK died because the teenage daughter chopped up the daffodils bulbs, mistaken it as onion, and served it up in a stir-fry for the family....
However, 1 leaf if it tastes pleasant is a trial I'm prepared to make. Daffy bulbs in the stir-fry: stuff of nightmares!
That's dreadful Florence. I won't be feeding Elaine my groundcover.
Maybe it is Swamp Pennywort (Centella cordifolia). If it roots at leaf nodes then it is likely. As you know, Centella asiatica is Gotu Kola. There are a few leaves that look like that. The native violet is pretty, I may try to get some of that and plant it around my garden, it may hide the nutgrass.
Nothing will hide the nut grass! I grows through asphalt footpaths. Only complete eradication will do any good. Native violet or the creeping one anyway, really prefers the shade.
Your weed looks like the Dichondra ground cover I have growing under the clothesline Florence. It's a creeper.
Your potted Gotu Kola has rather rounded non serrated leaves in comparison to the original description by Elaine. Don't doubt that it is indeed GK but it just goes to show the variations.
I got my Gotu Kola from Farina, have to ask her where it is from!