http://www.scottsprofessional.com/en/grass-growth-regulator.html
Maybe there was difficulty in saying 'H' properly so they decided to give it a miss.
Does spelling matter? Poor spelling might lead to a poorer vocabulary and, with fewer words, it is harder to develop shades of thought; poor spelling on a website suggests poor attention to detail which could reflect adversely on a visitor’s perception of the quality offered by that business; so yes, spelling does matter. We hope that we are being both useful and, at times, amusing. Please tell us of any errors that you find. Thank you.