f4forever wrote:

Current lawn in coastal NC is established centipede but don't care for
it's appearance. We had a lawn of St. Augustine in the past and
really liked the way it looked and the lack of maintenance that it
required after it was established. If St. Augustine plugs were
introduced into an existing Centipede lawn, would the St. Augustine
eventually spread and kill the centipede or would the Centipede stay
dominant and kill the plugs? Can't find anyone around here who can
give us a definite answer. TIA

there's a secret trick to being able to accomplish what you desire.
http://www.super-sod.com/info-guide-staugustine.html
http://www.super-sod.com/info-guide-centipede.html

look at the two different feeding recommendations I've provided.
notice the large difference in the recommended amounts of nitrogen
for the two different grasses.

centipede having a very low demand actually will not tolerate the
amounts of nitrogen used to feed and cause staugustine to thrive.

plug with staugustine and feed the entire lawn with the staugustine
feeding schedule. the centipede will go into toxic shock while the
staugustine thrives and takes over.

on the down side, good nitrogen is expensive. improperly applied
cheap nitrogen can cause environmental problems as well as damage
to small trees and shrubs.