Check out the mature width on helpmefind.com and plant accordingly. If the mature width of the roses you are planting is 3 feet, that means the rosebush will grow out 1 1/2 feet each way from it's center. By planting them three feet apart the bushes will touch when mature. Planting them 42 inches apart means there should be 12 inches of space between the bushes when mature. The mature size is influenced by your growing zone, how you fertilize, how you water, and how you prune. If you want them to grow together late in the season you can plant them closer together or if you want them to be distinctly separated you can plant then farther apart. When room is at a premium, you can plant them closer and keep them pruned back more. At one time I had 550 bushes on a lot 165'by 60' My roses were planted 18 inches apart. by summers end, they were terribly growing into each other but the effect was stunning. I could get away with it because I sprayed and the bushes experienced a lot of winter dieback resulting in much smaller bushes each spring as a result of the severe pruning required. In my larger lot here where I live now, the bushes are 3-4 feet apart or more depending on their mature size. I have less disease pressure due to better air circulation around each bush. That's something else to take into consideration.

This is what I call garden archeology, when you buy a house and have to figure out what the previous owners left behind, why they did what they did, and what to do with it. I would see what the flowers are and then decide. You might not even like them, so that would be a deciding factor. It could be rootstock, or the original rose mixed in with rootstock, which might be better removed. It looks like an odd placement that no one would have done deliberately, so it may be rootstock reemerging after the original rose was removed and the dogwood planted. Or the roses were there, and they just stuck the dogwood in for some reason. To me they look too close together for either to be happy, but you can't always tell from a picture. I would move or remove the rose and let the dogwood have the spot. If it turns out to be a massive climber, it could swallow up the little dogwood and do it no good. If it isn't, the dogwood will shade the rose quite a bit and do the rose no good. Matching the size of the rose to the size of the tree is important when trying to use a tree as a rose support. Also, if you live in a windy area, the rose canes can thrash around in the wind and scratch the heck out of the dogwood's bark. At any rate, congrats on your new home! Enjoy!

Round-up is sudden death for roses.... or any type of weed-killer...... either dig-dig-dig and get those roots up out of there, or do like I do, take some roofing shingles and lay on the weed and suffocate it.... leave it there for several weeks, and if you can't stand the look of the shingles just throw a bit of mulch on them..... sally

I had a similar problem. I removed the fence around my pool when I had the deck redone. I wanted a privacy screen close in so I used a combination of things. I made 5 trellises from 4X8 vinyl lattice and put them on landscape timbers about 2 feet above the ground and kind of framed them. Basically this made an 8 ft wide trellis with the top about 6 ft high. On two of these, i put Lady Banskia roses..they are evergreen. One one I am growing Confederate Jasmie and one one Carolina Jasmine (which isn't as thick a screeen as the confederate). The 5th trellis has another climbing rose but isn't really a good screen. I sort of placed these trellises at intervals around the deck toward the corners but not exactly symetrically.. In between these are a variey of other plants, viburnum which makes a bigger lush tree and lorepeltum for it's rich red coloration. The bed around my deck is of varying width from maybe five feet at the back of the pool to 10 feet on one end. So I also have room for compacta and some other hollies as well as day lillies, a few sago palms etc.. I used this other stuff for a low to the ground screen but also to give some texture /color differences. I've been shaping these other plants, some round, some square etc.. I'm definitely not a gardening artist, I just like to play and add stuff, but the effect is nice.