In zone 6a - all three of my butterfly bushes have foliage. One has new growth that is about 2ft high already, one has small growth from the base and the third was later than the others because it is in more dry shade and it just has a couple of stems. Sorry about your Buddleia. I wonder if the problem is that it is a recent hybrid and a dwarf? Sometimes, they are not as reliably hardy.

They don't go dormant. But that does not mean its dead..the cat knocked all the leaves is all. If its fairly healthy,it will sprout new leaves in time. If it is on the way to dead,then stems will shrivel,no growth at all..its gone. One way to check is to scratch the bark on a branch..if you see any green,its still kicking.

Dormant. It would have to be dry for months to be dead. It sounds like you're putting too much water on. It should not be soggy at all. You only need enough water to moisten the soil at the surface so the roots will knit in. You might try watering at breakfast, lunch, and dinner for 5-10 minutes. That schedule seems to be the "national norm" for watering new seed or sod. It depends on the heat, humidity, soil (sandy vs. clayey), clouds, rain, and the ability of your sprinkler to deliver water.

completely sodden the media.. presuming it has drainage.. and put it out behind the garage ... and then ignore it until fall ... you might be surprised.. lol ... i have found.. over the years.. that benign neglect works .. lol.. and no.. fert will not help it ... just dont put it on the patio where you sit every night.. and worry and think about it ... that will just make you angry ... ken