You're right -- it's a complex issue.

Ultimately, you would have to sue the HOA for breach of covenant/selective enforcement, and /or sue the neighbor for defamation of character.

You may want to contact local counsel and have a letter drafted to the HOA and to the neighbor, basically stating that unless this harassment ceases, you will have no alternative other than to take appropriate legal action. In some states, where another person engages in a pattern of harassing conduct, the conduct can rise to the level of a stalking crime. But, you will need some pretty credible evidence, before the police/sheriff will take the complaint seriously. So, unless the neighbor really gets abusive (yelling, pushing, stomping your plants, littering in your yard, etc.), this will remain a civil action and your only recourse will be a civil suit.

For a civil litigation attorney referral in your locale, see this link.

Hope this helps.

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