It turns out the law is in a body of statutes covering health and public safety. So my 1st thought is: that’s bizarre.. an ugly plant is a health issue?

It's been so long since many in the western world understood this but: yes. When those laws were written, overgrown lots in populated areas were a health issue. Sometimes they still are: Philadelphia specifically targets overgrown vacant lots because they provide an attractive area for rats to live, breed, and infest a neighborhood. The same thing happens with mice - and where mice go, snakes follow.

"But mice, rats and snakes are all around us!" Well, yes, they are. But we keep their numbers in check, and even the most eco-minded can change their opinions when it directly affects them: I certainly did when the two places on either side of me got foreclosed after 2008, and there was eventually an infestation of snakes, and then the snakes eventually started coming into my yard and my shed and my grill. Turns out what, while I'm okay with domesticated snakes, I'm kinda phobic about encountering them unexpectedly - like when I open the grill cover to start a barbeque and a family of snakes hiss at me.

Anyway, the problem is that, as neighborhoods with active infestations have faded into the past, people have started interpreting those laws as being more about beauty than health.

I'd start by making your overgrown area look more intentional. Keep the walkways well cleared. Put in some garden decorations and a birdbath. Maybe some bird houses, or decorative tree-hanging things. A chair and a small table on the porch or somewhere. Maybe trim bushes or small dense ground plants into nice even sides, that sort of thing - a bunch of small stuff that says "this area is intentionally wild, but it's also being regularly tended to and is under control".

You can foia request the complaint to find out who filed it.

Where I am, I've heard stories of people getting permission via hitting up local council environmental agencies and highlighting that you're doing it for environmental health reasons.

Keep us updated!

Usually the "health and public safety" attempt at rationalization is that excessively tall grass "harbors vermin." (In other words, "creates habitat for wildlife," but spun as a bad thing.) "Weeds have toxins and allergens" seems even more grasping at straws than usual.

At one time, a local parish sent me an e-mail admonishing me to make hay.

I was tempted to at least insult them, but failed to bother and didn't even reply. I only mow down the plants which cause me allergy in late summer (Artemisia vulgaris).

Later, certain people got pushed out of the parish self-government and they sent me a letter that said I had a protected area for bats.

I was tempted to remind them that if I had made hay every summer, there would not be trees growing here, and bats would be elsewhere. However, knowing that the idiot who wanted everyone to make hay was already terrorizing people in another parish - I again failed to reply. :)

So are you going to fight the citation? Better have lots of pictures with botanical data on all the plants growing in your lawn. Seems the key element here is the legal definition of a prohibited weed. If you go to trial, give the officer some rope and see if he'll hang himself. Ask if he's an expert on identifying weeds. If not, how does he know your yard had weeds? Otherwise pursue his qualifications. What training is he relying on to identify weeds. Make him define a weed. If it's substantially different from your legal definition, ask whether he's aware of the legal definition. Introduce the legal definition and have him read it. Then ask if in light of his newly acquired knowledge, does he still maintain that your yard had weeds. If not, citation dismissed.