I cut all of the old branches out of my rose bushes and now they fall over. I have to tie them up with string. Did I ruin them? I live in Bakersfield, California, so the roses bloom all year long. Also, I trimmed one rose bush back to the fifth leaf and now I have no roses. These rose bushes usually have 100-150 blooms at all times. We had a heavy rain (we usually only have rain a few times per year) after I cut the old branches out and they fell over. I'm afraid if I untie them they will just fall over again.
It sounds like you need to provide a trellis for the rosebushes you mention and tie them off to that, at least until the younger canes gain the strength they need to stand up better. They have grown up being used to the support of the older canes, once removed they need to kind of figure things out for themselves. Be sure to feed your rosebushes with a good organic rose food that builds the soils and feeds the bushes. Also give them some super phosphate to help strengthen the canes. I also recommend giving all the roses about 1/2 cup of Epsom Salts scratched into the soils and watered in well.