Dear Sarah: Yes, your weigela plants could still be alive. They would be slower than those already established, due to a limited root system. You could do a "scratch test" to find out the condition. Using your fingernail gently scratch the bark off of a twig in one place. If dark green in color and a wet apearance, the twig is alive. If a pale dry green color, it is failing, if dry and brittle, it is dead. I would wait a while longer before considering replacement. Contact your nursery or garden center and ask about any guarantee.
Hope this helps.
