Can anyone tell me why my 2 previously identical lavender plants look like this?!

[hudyerwheesht]

Bought and placed as shown in pic at the same time. Both watered at the same time when needed.
One side -the one with the dying plant - gets less sun than the other but not hugely so, it's a south east facing deck so generally a warm, sunny space.

It happened last year too (with a different pair of lavenders) - I ended up swapping them periodically and that basically led to them both dying as whichever plant was moved to the shady area wilted.

Any ideas?

is there a dog?

Did you look at the root of the dying one? There could be a pest in that place.

I had four identical pots in identical aspect places. Everything I put in the fourth one died. Eventually I took all the soil out and found about a billion grubs right at the bottom of the fourth. They were eating all the roots.

No dog, or cat.

Haven't checked the soil at the bottom of the pot - the fact that it happened this way exactly last year meant I was thinking of the location rather than the pot/plant itself.

The decking is raised quite far from the ground, could there be something still managing to get to the roots, even through the pot/saucer?

Grubs, urgh. Will check tomorrow....

Ok, checked the roots/soil at the bottom - nothing sinister there.

Anyone any ideas?