Here in a colder zone they are just coming up. In z8 I would expect they would all be up by now. Are trees leafed out?

Did you plant them in fall or recently?

they didn't grow tall last year, so i just left them in the ground.

did some kind of pest worms eat them in the ground?

It's possible that they rotted. What type of soil did you plant them in? Is it well drained?

It's also possible that some type of rodent might have got to them. Do you have any rodent problems?

Rodney

Yes, quite possible they were eaten.

Jerusalem artichokes are quite late to show here. Mine are not yet up. BTW 'germinated' applies to seed, tubers just 'come up' or 'sprout' ;-)

If the old stems are visible you could dig carefully down a bit next to one and see if there is any sign of growth.