[MikeHardman]

One of my little lavenders (cuttings 13 months ago) has become the focal point for an ants' nest. It is gradually disappearing as  a pile of soil grows up through it. My first thought was to get rid of the ants. But I couldn't help thinking that the soil had a lovely fine airy tilth, while being slightly damp. ...And I wondered if the lavender's branches might layer themselves into it. It is a little experiment (or ongoing observation).
I will have to keep an eye on things to make sure the lavender does not disappear under the soil. But it is no great problem if I lose the plant.
I could kill the ants but leave the soil there. But, with the winter rains soon to come, I think I'll keep the ants: they would work on their nest to re-aerate the soil if it gets too wet.
Folks: what do you think?

[Umbrian]

I have had this problem too Mike and have just knocked away the soil and redistributed it after killing the ants. As you know though they are impossible to irradicate altogether and they just move onto another subject , usually another Lavender  which they seem to favour. Those of mine that are most affected are the ones in my pool border which I like to look presentable especially during the summer months hence my efforts to get rid of the ants. It will be interesting to see if your experiment works though. My fear has always been that eventually they will kill the plant altogether apart from looking unsightly.

[MikeHardman]

Update:
The ant's nest was abandoned during winter, and the plant continued to grow well. Now, with blooming well under way, the only obvious evidence of the prior ants' activity is the lack of flower on the affected part - as the photo shows. Now I must remember to excavate to look for any signs of rooting into the ants nest tilth...