By synchronicity I mean that which causes a like response in others. Have
you never been to a boring party when one person yawning sets off the
others? BRBR

That has absolutely nothing to do with plants, and certainly nothing to do with
the flowers on your rosebushes. Synchronicity in plants occurs as a response to
natural phenomena, for example the Dendrobium where all the population of an
area bloom exactly nine days after a drop in temperature. Please watch out for
anthropomorphism.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)