I would dig them into the ground. I've never added extra holes to the pot. Everything is going to freeze up anyway. Best put a layer of mulch over top too. I think it keeps it from freezing too hard (maybe or maybe a myth) If you leave it on the top of the ground it WILL freeze too hard.

Okay thanks! Should I do that in November or should I wait? Also, should I put something over them to protect them? They're both zone 3 hardy so I'm guessing they'll be fine, but just in case?

Most common advice is that plant should overwinter in container without extra protection in zone 2 higher than plants rating -so if you are in z5 and they are hardy to z3, should be no problem.
But insufficient drainage will kill many plants, so make sure that is adequate.

You could put them in ground, even just halfway but make sure the surrounding soil is well draining too and that there isn't any standing water around them. If you want to add extra drainage holes it won't hurt, drill some into side of pot close to the bottom.

Mulch (like fallen leaves) is good protection, should be put on soil surface after hard freeze - just as recommended for garden beds.

Tops could use some protection (like burlap) if they are in windy location or very close to road (salt?). Otherwise, I think, they should overwinter OK if they are in appropriate zone. Don't fill with anything like straw, you may create too damp conditions.

Rina

It's nice to see that you're thinking ahead!

Planting in pot is a good option if you have very freely draining soil. If you have clay soil like many of us do, then putting the pot in the ground over the winter is a sure death sentence. In that case, your best options would be (1) bringing them into an unheated structure like a garage over the winter or (2) placing them in a sheltered location outside such as the north side of your house and mulching over the pots with straw, shredded wood mulch, or leaves as Rina suggests.