Compared to all the other work you do, weed-pulling may be a little redundant, but for me personally, it's my least favorite work to do. If I could get away with it, I would charge more per-hour to pull weeds than any other service I offer. Unfortunately, being such a simple task (though tedious), people simply will not buy into that. It's very difficult to make the same cash per-hour as other services (i.e: mowing, mulch, stone, etc.), but I would make the best of the situation, be diligent, and prove your liability to the customer. In fact, weed-pulling is one of the best ways to upsell another service. For example, if the weeds are an empty bed, you could suggest laying down some weed-prevent fabric, and put some nice mulch on top. Adds a nice positive to the negative IMO.