I have never heard that about deadheading. I have been doing it at least 20 years and not had any issues. I was once told not to take scapes off until they pull easily for the same issue.
I actually "livehead" in the evening of the day the flowers are open.
Here are a few of the reasons...
No yucky old blooms to handle
Spent blooms can droop over unopened buds and keep them from opening properly. If you livehead this won't happen.
Just my opinion, I have no proof...but I think I have less slug and earwig issues because I livehead. No yucky stuff on top of the scapes to attract them.
The garden looks very fresh first thing in the morning with no old blooms
You don't risk breaking petals on the new blooms because they are not open yet
Fresh blooms won't stain clothing or fingers as much as spent blooms.
You can still admire the blooms as you pick them. I like to stack fresh blooms in my hand, one on top of the other. Much more fun than a handful of spent blooms
I carefully grasp the bottom of the bloom, and break it off. Sometimes I will stick my thumbnail into the very bottom of the bloom, then snap the other way. Kind of like cutting a wedge in a tree the way you want it to fall. You will get a feel for doing this without breaking unopened buds.
If I have pollinated a bloom, I do wait a couple days, then carefully cut right below the bottom of the bloom. Make sure to cut close to the bloom, not close to the stem.
I find it a pleasant task to livehead, but a chore to deadhead the next morning.
Hope this makes sense.
