Americans call celeriac celery root.

And I’ve frozen roasted bell peppers without issue. Any roasted pepper in fact. Bought a bunch of poblanos last week and will roast, skin and freeze them today.

Why do you roast them before freezing?

Generally, to remove the skin so they are ready to use (poblanos). Usually the Peperoni are leftovers.

Because if you don't, they will come out like mush.

Tom

The internet said they don't.
Okay, I'll take your word for it.
But only because it sounds logical. I like logical.

That leads to an other question (as I don't like peeling things as long as their not oranges and bananas etc.):
Can I roast them and NOT peal them and freeze them?

They're easy to grow, I always have them in my allotment too. Need a tad more water and feed than 'normal' and will reward you with lovely big bulbs.
Last year I used some of mine (stalks and bulb) ampng a few other veggies to make my own vegetable broth powder (Gemüsebouillonpulver)

Yes. The white part I might also leave for another time. I’m quite surprised anyone would throw out the green part.

I like the stalks of broccoli and cauliflower. But I don’t cook them separate. I don’t mind if they are a bit less cooked. Though I do cut them a bit smaller.

Of course they are! I’m living proof. It’s only a bit more chewy. You know. Fiber.
I eat them because I like the taste of the seeds.

I often peel them once I thaw them but sometimes I peel them before I freeze them. After thawing helps them keep their shape. If roasted properly, should be relatively easy to peel.