the truth is that any grass will juice up just fine and be super healthy for you. i have juiced about 6 different species of grasses and they all did good things for my health. any of the wild grasses that develop a seed head are wild relatives of our (highly hybridized) wheat plant. but the thing is its best to harvest the grass before it develops a head, since most of the nutrients and minerals get concentrated in the seed head.
the good news is that you can still utilize the seed heads - for grass head tea. just strip the seeds and make yourself some tea with them, its very mild and very nourishing, full of good stuff.
i love to harvest my food and medicine direct from nature.