According to this recent study, the main ingredient in the herbicide Round-Up may be killing honey bees and our native bees.
There are many safer alternatives, for you and the bees. Check out clove oil products like Weed Zapp. I’m having good results on tough desert weeds with amonium nonanoate which biodegrades in about a day (for example, Biosafe Weed Control) but it doesn’t smell like cookies like Weed Zapp. You can even steam your weeds to death!