There are varying opinions on which is better where. In cold zones it can be an advantage to have own root plants if they die all the way back to the ground over winter because you won't lose your variety when it regrows from the ground up. On a grafted rose if the graft freezes and dies over winter you've lost your variety and there is a possibility that the root stock rose will come up instead. But if you plant your grafted roses with the grafts 4 to 6 inches below the ground that's usually good protection for the graft anyway. So it's rally up to you which you'd prefer. And there are some varieties that you can only find as grafted roses. That's changing but it's a slow process a driven by market demand.

Grafted roses will grow and mature faster than own root plants. That's the point of grafting one variety onto another. The root stock variety is usually a very vigorous grower and will cause the grafted variety to grow faster. Own root plants will grow but at a slower pace depending on the variety of rose. There are some varieties that were bred specifically to be grafted and a lot of those varieties will tend to not do very well as own root plants. They are just not very vigorous on their own roots. The problem is it's hard to know which ones those are because for a very long time almost all roses were sold grafted and own root plants were very rare. So roses bred in that time frame may or may not do well on their own roots. For the most part those are hybrid teas that were bred from about 1930 to 1990. That's a lot of rose varieties!

Another thing that should be noted in regards to an own-root rose: they are usually quite small plants, smaller than grafted plants, and because of their smaller size cannot always establish enough in a single zone 5 growing season to survive the first winter. If you choose own-root try to get the largest plant possible.

Here's a video where a well-respected rosarian explains & illustrates his thoughts on the subject. I've come to favor ownroot over grafted for the reasons he mentions & also find them healthier in general & more graceful as plants. Mulching & protecting an ownroot rose it's first Winter is the same for me as any perennial planted that year, and I'm in a warmer zone.

Seems the roses offered ownroot are those that do well on their own roots. Tend to buy gallon sizes, usually older more established plants, and larger if available.

Here is a link that might be useful: Paul Zimmerman Difference Grafted & Ownroot

Some roses do GREAT on their own roots. Others lack the vigor to thrive unless they're budded. So, the answer is "It depends . . . "

Own-root plants certainly start out more slowly, but many of them can become enormous, given time and water.

I prefer own root roses in my z4 area IF the rose is vigorous growing on its own roots. Most modern shrub roses, minis, & OGR's do best own root. HT's & grandifloras tend to be not very vigorous on their own roots plus slower to wake up in the spring so I want these guys grafted. Floribundas are a mixed bag so some do well own root & others do better grafted.

Great information! Thank you so much for all the advice!