Are they going to survive this or did I just ensure their demise?

I felt like a butcher cutting them back the way I did. I made sure I left leaves on the stems and all that. Some of the stems though are exceptionally woody looking and others arent. I'm not sure why. This is my first time growing petunias.

and it is about that time in the season ...

next time..when you have multiples.. experiment.. cut one or two.. and wait a week or two.. to see how the plants react ... then go for it ... based on the result ....

i would have looked for tiny buds at leaf junctions.. and cut back to such.. rather than randomly cutting away ...

but i doubt it would make a difference ...

if they perish.. it will be that there is some other problem ... like drought.. or potting media.. etc ...

they are annuals.. and sometimes.. as such.. they just peter out this time of year ... oh well ... you cant win them all ....

ken

Your severe pruning should only improve their appearance; just maintain a dilute but frequent feeding schedule and your plants should rebound beautifully for a beautiful late summer and fall season.

Petunias aren't carefree. Deadheading and occasional pruning are necessary to prolong their productive life, as is a fertilization program. With a little bit of care, you'll find that fall can be their best season.