There are a lot of right ways to grow roses.  I have been told that roses are "heavy feeders", but over time, in my own garden, I have found that it varies by plant.  I have some roses that I feed every other time I feed roses.  There are others that seem to need more iron.  In my opinion, most of what you feed your roses depends upon your soil and what nutrients seem to help the plants have more vigor.  For example, I never used epsom salts in southern California because the soil was already alkaline, but there are people who grow roses down there who will tell you that it's absolutely necessary to use epsom salts to get better basal breaks on budded roses.  I can't say they are right or wrong, because I know only about what worked in my garden.

Mr. Ralph Moore has said whenever asked questions of this nature to remember that "roses can't read".  In other words, experimenting with what works in your own garden is the best way to find out what works for you. 

Rule of thumb is that organics take longer to break down and have the nutrients available to the rose for food.  I don't buy special food for roses, but have found that some plant foods seem to work better for me.

A very good practice is to water your roses very well the day before you feed your plants.  Roses have their feeder roots near the surface.  If you have watered the roses well, there is much less chance of burning the roots with anything you use to feed them.

If you do a search of the Q & A Forum archives, you may find more specific answers to your question.

Smiles,

Lyn, helpmefind.com

Lyn is very correct, there are many 'right' ways to grow roses. What I would suggest if you are new is feed them a well balanced flower food. Such as 10-10-10 or 20-20-20  or as close to a balance as you can find. Follow the directions on the package.  Tomato food is good for roses too.

I've had good luck with alfalfa pellets as a slow release feed. The roses seem to love it, just make sure it doesn't contain salt, sugar or molasses which for  animals not gardens.  I put down two cups for each bush around the root zone. Keep it away from the canes as it can burn them.  I put down alfalfa pellets in the Fall they break down over the Winter then feed the roses in the Spring

Epsom salt has magnesium which the roses like and you would use one quarter cup per bush around the edge of the bush per month.. DURING the growing season.. it's too late for that now. 

You need to be careful with manures. If they aren't fully decomposed (the less they stink the more decomposed they are) manures can burn feeder roots. In addition one of my dogs(and others I've heard of) like chicken/turkey manure. This dog has dug up roses to get the manure.  Make sure it is well aged and don't get it too close to the canes as it can burn them.

Don't get so caught up in doing it 'right' that the roses become a burden rather than a joy.  Roses are much hardier than some give them credit for.

Best of luck