Is there any need for alarm?

We used to have six massive rhododendron bushes in our front garden that
produced a wonderful wall of colours about this time each year. Over
the course of many years, never once did we find a little rhododendron
sapling growing anywhere else in our garden, or for that matter in the
surrounding fields. Those rhodies simply never spread - despite our
garden and all of the surrounding land being highly acidic, quite
temperate, and ideal for the growing of rhodies..

Then we moved house about three years ago and missed the wall of the
colour, so we planted a dozen small cultivated rhododendrons purchased
from a local nursery.

Along comes a neighbour yesterday with fear writ large all across her
brow and she warns us we had better cut every single flower off once
the petals have fallen OR there'll be rhododendrons everywhere and local
farmers will be furious with us!

There are no other rhododendrons in gardens in this area, though
largely, I suspect, because most of this area is more alkaline than
acidic. We are fortunate in that our little patch is quite acidic.
Could it be that the fear of cultivated rhododendrons in this area has
resulted from the fact that people can't grow them here and are ignorant
of them?

Have done a brief google on this subject and found that "Rhododendron
ponticum" can spread.

Thanks.

Eddy.