die out
die off

But then it got cold and those trees died off.

Some groups may survive the winter, once the old people have died off.

One after another, her children died off from various diseases.

We'll have to wait for some more of them to die off.

This practice seemed to start in the early 2000s and has not died off at all.

May I cut them now or wait until they die off?

These appear to die off after a few weeks in the water, but this is not actually the case.

And we're going to be around after you've died off.

With the end of the war, the Project appeared to die off.

The smile died off her face when she saw me.