That foxtailed, goat head mess across the street

We live in the country pretty much so across the street is what in most areas is an easement (not here)and being that is considered a private street no one takes care of it. Now my husband or the boys go out once a year to weedeat it down but I want to see something besides weeds. Tall weeds.
I will buy the seeds, but watering is almost impossible. Does anyone have any ideas? I don't want to take care of it I just want it to grow.
Is that possible?

In a word - no.

Even xeric plants must be watered in for at least the first year, especially since you would be starting at the worst possible time - the dry hot summer, instead of the cooling late fall rainy season.

Consider instead planting a leafy screen at the edge of your property, for which you would be able to eke out precious water.

You and your family are to be commended for weed-whacking the street down! It's a fire danger, too, if left untended.

Unfortunately there aren't any easy solutions, anything that you do is going to require a good amount of effort (otherwise, if it were that easy to get rid of weedy fields, we wouldn't have any! LOL) You could try sprinkling native flower seeds in the fall, assuming they don't get eaten by the birds or the seedlings choked out by all the weed seeds that are germinating at the same time you may get some plants that will get by only on the winter rainfall. But if you really want to see something besides a CA poppy scattered here and there throughout a field of giant weeds, you're going to have to do something about the weeds, otherwise they will just choke out your plants (which is what they already did to take over the field in the first place)

You could solarize during the summer to kill the weed seeds, then spread a good amount (there are guidelines on seed sites) of native wildflower seeds just prior to the first rain. If the mix includes different blooming times, it might last for a while. Like ecrane said, no easy solutions.

We are faced with the same dilemma here, and have to contact Caltrans, who bought the property across the road, to see what can be done.