I'm not sure what "spot about roses" you mean or who "they" are but it's totally illegal to cross the border with uncertified roses. That's not to say that they will find the roses, but I for one do not mess with Customs. It's not even legal for Canadians to mail you seeds. Sorry.

I would definitely check with your local Ag Extension or whatever you have and they could advise you the best way to get the roses. I know there are some Canadian companies who routinely ship to the States but they do have to provide phytosanitary certs. I think if you arrange to have the phytosanitary certificate prepared for your pick-up, so you can present it to Customs at the border, it is ok. This usually costs about $10 I think. But I still don't see why it would be any cheaper or easier to drive up here than to have them shipped.

You have to get a phytosanitary certificate from the Canadian nursery selling you the roses. This assumes the nursery is able to issue the certificate. If you are intent on getting the roses from Canada, contact the nursery in Canada about the phyto and cost.

I will post a website from a Minnesota mail order source which has a decent selection of Ag Canada roses.

Do you ever go to the Twin Cities or in that general vicinity? There is an excellent nursery in North Branch that has reasonably priced hardy roses....some Canadian. There are couple of other options. One of my favorites is on the way to Duluth. Email me if you want particulars.
Jan

Here is a link that might be useful: Kedem Roses

There is a nursery in Wisconsin that specializes in hardy roses. I only wished they offered more truly old roses when I gardened in that state.

Here is a link that might be useful: Spring Valley Roses