Ants under lavender

Dear gardeners, your help is needed, please. I planted 5 lavenders the same day from the same shop. They all look different after two months now. I presume the size could be different because they are placed on south-west side and do not have equal amount of sun.
The thing that worries me is that those bushes in shade in the afternoon, have kind of dry stems inside, while those on full sun are fine and bigger. I thought it was because they were on higher “hill” ( when planted made a bit hills to avoid damp) and some roots were not covered with soil properly after pooping with water. I dug one out to deepen it a bit and was shocked with what I saw: ants made the roots their home with a lot of larvae! I though it was the reason this plant suffered and tried to get rid of them manually. Planted it back, blossom straightened up in two days time but the bush like is drying out inside.
Can ants cause a problem or they cannot affect lavenders? If they can, how to get rid of them but save the plant?
Many many thanks for any advice

 

@Yana Ants are not generally damaging to plants' roots. Their tunnels can of course take away useful soil from the roots, but that should not be so massive to interfere with plants growth, I think.

One thing that ants do which is damaging to certain plants is farming aphids. Aphids are small creatures which feed on the lymph of plants. Ants eat the secretions from the aphids, so they protect them from predators and even carry them over the stem of plants.
This makes it very hard to get rid of them, because as soon as we remove the aphids ants will will bring more aphid eggs.

The kind of aphids I am familiar with grow on top of certain kinds of plants, however here it says that there is such thing as root aphids:
Root Aphids: Learn How To Kill and Get Rid Of Aphids On Roots

If what you have seen are actual ant larvae, they should not be a problem for the plants, I think. If they are root aphids, they would be a pretty bad problem, I understand.

Ants can be quite hard to get rid of. They do not like damp soil, so watering a lot could help.
You could consider planting your plants in bottomless pots, with good potting soil.
Essentially, you would be giving a good start to the plant, which could then extend its roots below the pot once it gets large enough. If you watered in the pot, you would keep that soil moister than the rest of the soil, making it less attractive to ants.

But frankly I have no experience with lavander specifically. In the wild, I know it as a sturdy plant which is happy in dry soil. Perhaps others might be able to give you more specific advice.

 

My guess is that unwittingly you have planted the lavender on top of of an ants nest. Since planting the ants have become active and in doing so they have loosened the soil around the roots. The lavender is actually suffering from dehydration due to the roots not being able to working properly.

 

just water regularly the ants will quickly go as they hate wet soil

 

Lavender likes drier poorer soil generally. but a quick jet of water should disturb the ants enough to move. Ants are common in our garden and disturbing them means the birds enjoy a feast on their eggs.

 

Thank you very very much to everyone (unfortunately, I was not able to reply in quoting due to error every time I tried to do so) but every answer was informative for me and I appreciate all your help. I kept watering it but they are still there and I am not sure if I can use the method described on this website to get rid of ants by watering with vinegar or washing liquid if they are based under my plant (I am not sure Lavender would like it)