Legal Question in Real Estate Law in California

Re: Bamboo

Trespassing roots and limbs are an exception to the general rule that a victim of trespass should not resort to self-help but must get relief by court order. A property owner is allowed under California law to trim invasive roots and overhanging limbs at the property line, but in exchange for the privilge of doing so without resort to the courts, must observe two additional caveats: the trimming must be done "in a non-negligent manner" (to quote one court), and the cost of the work cannot be demanded from the trespasser. "Non-negligent" was left undefined by the court that used that expression, but it's usually thought to mean doing the trimming so that the tree (1) is not permanently injured or (2) does not become a blow-over hazard in a windstorm.

Of course, a victim of tree-trespass also can go to court and seek damages on traditional trespass and/or private nuisance grounds, and in doing so may get a much more satisfactory result, including money damages for the consequences of the traspass (pruning costs, replacement costs for broken concrete, etc.) and/or an injunction against future trespass or nuisance.

It sounds as though your neighbor has a partial understanding of the law, but is mixing theories or is partially wrong. You might want to offer mediation with a mediator well-schooled in the law of trespass and private nuisance, in order to avoid the costs and hassle of suing a neighbor, but do keep in mind that a court would probably give you a better deal than the neighbor is currently offering, especially if your lawsuit were carefully put together, well pleaded and supported by good evidence.