I just dug up a Sago Palm that was killed in a recent hard freeze. There were many pups attached to the roots, two of which had leaf growth coming out. Certainly those two will get replanted.But what about the others? No green growth, no roots, no anything. Should I bother to plant those, hoping that they'll eventually decide to sprout? Is there a way to establish whether they are likely to be productive?

Plant them and see what happens! If you end up with too many, you can always put them in a garage sale. Those things tend to not be a cheap plant on the market. I sent mine to Austin because it got to big to manage here and it was too awkward to move in for winter protection from freezes. It got zapped by them a couple of times, but always recovered, so I knew once it got really large it needed to head further south.

Well, yes, that's an obvious strategy. Just plant 'em and see what happens. I was wondering if there was some way to judge their viability before doing that. Does one just assume that any pup is viable, if it wasn't mistreated, or are there duds?

Kind of odd, we had three serious freezes (<10F) in the last two years. The palm survived the first two, but the last one, which was barely below 10F, probably the least fierce of the freezes, took the (rather large, 4 feet high) plant out entirely. No way these pups saw any of those temps, because they were underground, so I'm hopeful about them.

Perhaps duration of the freeze? The <10 here last about 36 hours. That's a long spell for temps that low. Overnight is one thing. When extends beyond that the cold starts penetrating in a way that shorter hours of freezing do not. Makes the warmup slower too.

Freezing temps are somewhat unpredictable in the damage they mete out. My little pomegranate had put out before the last frost. To all appearances that frost killed most of the above ground growth. It's beginning to send up suckers, but the main trunks aren't showing any recovery. A lot of plants that got bit seem to be having trouble recovering. A big oak that was green is just showing new green growth this week. Trees that were just barely showing swellen buds are way ahead of it now.

I have no experience with Sago pups, so can't guess about their chances. If they are clearly still alive, I'd think there was hope. Sagos are notorious for seeming dead and then recovering completely given time.

Yes, I gave my Sago a few months to show signs of life.There was none. Usually only takes a few weeks.

stick them in 1 gallon pots of potting soil and see what happens

Can take a year and sometimes more, but chances are the crown froze - which kills them. Pups can come from male or female sagos, but if they are green now, they are alive. Freeze damage shows up yellow in fairly short time.