Do I need to protect perennials?

[LA47]

I planted the penstemmon and the jacobs ladder in the ground, after hardeng them off, 5 days ago. It is suppose to get down to 31 degrees later this week. Should I cover them?

[rainbowgardener]

shouldn't really be needed, they are cold hardy.

[Susan W]

I'd cover them. They are cold hardy, but this chilly spell may knock them back in their growth. The roots may be fine, but your pretty new leaves could suffer.

[LA47]

Thanks for your replies. I'll keep some towels handy and cover them.