C.cheiri is technically a perennial but is so short lived that it is used as
a biennial.
They will flower now but are then of little or no use and are thrown
away.They are replaced in the autumn from seedlings sown and grown this
summer.
You might be able to keep them alive but they will never flower so well
again, even if they survive.
There is one variety~Harpur Crewe~that is only propagated by cuttings.
Best Wishes.
"High Nonnie" wrote in message
...
Can't seem to find the answer in my Sunset bible, or on the net, so
asking this good group.

Thses are established, 2 yr old, plants and blooming nicely. Should one
cut them back at some point? Do they take well to dead-heading? Plants
are quite well filled in and close together and I'd like to keep them
so. Don't want them leggy.

Your opinions appreciated. TIA , Nonnie