I'm fascinated that there is not a single first hand account about the ethnicity or legal residence status of the landscaper and yet somehow we have determined that they are illegal.
Put down your pitchforks and torches.
I'll throw down a plausible explanation that doesn't require painting with such a wide brush.
If the hops were grown on property that the HOA maintains, the covenants of the HOA require them to maintain (my supposition) a finite variety of plants. The HOA has a desire to keep things in the community consistent and vanilla so as not to offend anyone (think McDonalds).
Our HOA, if it can be believed, does not have native AZ trees on its list and so wildly growing saplings of mesquite are routinely hatcheted.
I think that the HOA may have cut your hops on purpose or at the request of another homeowner.
I think the landscape guys are being scapegoated and if the hops were planted on the community property, (Again, my assumption based on the fact that the HOA maintains that area) then you rolled the dice and lost.
OP, Please correct me if any of my assumptions were incorrect.