Hello Kevin and sorry for the delayed response. In Savannah, we do not use growth regulator or any other chemicals around our monuments. The main reason being that these chemicals can be absorbed by the stone and have long-term harmful effects on them. It is a catch-22 however, as improper line trimming can cause damage to the monuments in addition to the added time and money. I recommend contacting the Chicora Foundation for advice on this topic. They have done a lot of workshops and presentations on proper care and maintenance of historic cemeteries and, therefore, would be an excellent resource. They will be at our 2019 conference in Savannah too!
Thanks for the very kind words! If this is still an issue: among the 100+ cemeteries for which we have prepared assessments, I can remember only one where we considered a growth regulator a possibility. For those not familiar, these herbicides block the plant hormones that stimulate growth. They may reduce growing height, reduce seed heads, and increase turf density. BUT, they must never be used on turfgrass with poor root systems or growing under stress due to poor soil conditions, drought, disease, etc. In addition, many (not all) can be hazardous to animals (bees, butterflies), and pets - so you must be very careful in their use. They must also be prevented from drifting and this can often be a challenge. Many of them are considered corrosives and are acidic.
The biggest problem from a practical standpoint is that the growth regular must be paired with the growth for which you desire control. Many of the cemeteries we see present a "mixed turf" - largely weeds, but often some centipede, Bermuda, etc. This is a problem trying to select the correct growth regulator.
In addition, what many cemeteries want to "regulate" are the weeds - with the exception of Bermuda, most turfgrasses don't grow all that fast. Centipede in particular is a relatively slow grower and it has a low N-requirement.
Finally, these products are not "miracles." For example, Ethephon in one study suppressed mean centipedegrass vegetative growth by 15% with no turf injury. That isn't really a lot given all the issues and costs.
Best, Michael Trinkley