Regarding Artemisias ~ regardless of the effect on edibles, the root system will compete with moisture and nutrients for your edible plants. It is best planted in its' own area.
Not sure which Artemisia you were thinking of. Your first link took me to a plethora of keyhole gardening photos.
Perhaps some of the Lambs Ear plants might suit you. They will form a mat of that same silvery color and act as a mulch for your edibles. They are also medicinally useful as an herb.
I would also look at the French tarragon as mentioned above.
I have two of the Artemisia. One sends out incredible runners when in ground. It pops up everywhere. When in a container, plantlets pop out of the drainage holes. The other is still in a container and appears to be better behaved but still grows to be a monster plant.
The thread "Two different Artemisia ~ any thoughts on ID?" in
Plant ID forum
Not sure Artemisia would be suitable for your edible application... Kristi
