I planted fruit trees early in the spring and just mulched in 6 ft diamter around them. I'm thinking of ordering some live comfrey and live camas. Its September in MA, am I too late?
I like to plant stuff in early Spring, or Fall. so you're not too late, but you might be a little bit early.
comfrey isn't very picky, so I think you would be alright just about any time with that, so long as you give it some water. I would wait on the camas until the plants are dormant.