It is possible. The best looking plants you get from T-budding on a young rootstock, planted in spring, perhaps on the second season. They get courser by the years, and it's harder to lift the bark from the "rootneck", place the bud-eye, and make it grow well together.

The other types of grafting common on fruit trees are not as much used on roses, it works, but it can look a bit awkward, especially on smaller shrubs, floribundas and hybrid teas. I have seen plants where the owner have grafted on several varieties on a big plant, and it can look fun.

Do you plan to "add" Mermaid to the existing red climber, or rather let Mermaid take over completely? Mermaid often needs a few attempts before it takes. However, you are probably better off budding Mermaid on a young plant, or root a cutting.

Not sure if the rose about which you are speaking is growing at the corner of your lot, or the corner of your house? If at the corner of your lot, Mermaid might be fine if you have a space 20x20 feet where it can grow and not interfere with the neighbor's yard, the sidewalk, the street, etc. If it is growing at the corner of your house, I would not use Mermaid - it will eat your house! Think Sleeping Beauty's Castle after the 100 years of VERY thorny vines have grown up it...

There are lots of nice yellow roses, and also old roses, that you could try instead.

Jackie

Sure, you could do what you suggest, but may I ask why??? Mermaid grows like a voracious house eater on its own roots, and quickly. I have no idea what Mermaid would do on Dr. Huey roots, but my educated guess is that the Dr. Huey rootstock would actually restrict the size of that Mermaid plant, not enhance it -- just because Mermaid is so huge to begin with, and because it is a hybrid bracteata -- which does just fine ungrafted. If you want Mermaid, better to take out the Dr. Huey (I assume that's the red rose you have -- which is actually rootstock from some prior iteration of grafting), and just plant the Mermaid there.

OK, so I guess I don't want mermaid. I'm just looking for a nice yellow climber that will grow on a trellis on the corner of the house. Had no idea Mermaid was such a monster.

The reason I was hoping to graft on to the existing rootstock is that it is so well established I thought perhaps I would get a larger set of canes faster. Am I wrong? Would it be better to dig the whole thing up and start over? Not sure exactly which rose I have. Still waiting for it to bloom. The previous owner described it as "that boring red rose that grows everywhere"

So any suggestions on a variety for this location? I guess I'm looking for a yellow climber, not too agressive, fragrant and of course disease resistant.

Yes, for the best looking plant you need to dig up and plant a new. Light yellow looks very good with a red rose, so you might want to keep it :- )

You could check out Leverkusen, or Golden Showers, they are old favorites and not sharp yellow. Penny Lane is more pale pink-apricot, but very nice. They are worth checking out if they do well in your area. If you go for something with rebloom they tend not to grow too large, and take pruning better.

That "boring red rose that grows everywhere" is probably DR Huey rootstock from another rose that was planted there. It's a very vigorous grower which is why it's used as root stock. When you dig it out you'll need to dig BIG and DEEP and hope you got it all or it will come back.

For a nice yellow climber my first thought was Golden Showers too. But there are a lot of beautiful yellow ones to pick from.