Is this a brand new bed that was just planted? True 100% clay soil is not anything to plant roses in. If it has been a flower bed for a while, I would just cover it with 2 inches of mulch (not touching the base of the roses, and see what happens. Also try and figure out if you can improve the drainage.

Jackie

Plant potatoes for one year to loosen the soil. Any weeds should be tilled under after removing potatoes. Then work in wood mulch, lime, volcanic rock gravel, and perlite or coarse sand to lighten the clay and improve drainage. Probably in a 3:1 ratio, it takes A LOT to fix clay. You can experiment with the ratio by taking a #1 gallon of clay and mixing in everything in a #5 gallon nursery can to get the texture you want, that will be your ratio and just extrapolate.

The easier method is building raised beds 24" - 36" high, nailing galvanized chicken wire underneath to keep away pests, and filling it with good garden soil from a bulk soil company. The rose roots will go into the clay if they want but won't suffocate in the raised beds.

Ignore the first paragraph of the post immediately preceding and give the second one serious consideration. Or if you really can't undertake a big do-over mulch as previously suggested.