Tracing the history of a particular rose can be a fascinating adventure, but it is hardly an exact science. The old roses have cross-bred so many times, and so many varieties have been lost to time, that it is often impossible to uncover the exact parentage. If you are one of the many who become possessed by roses, you may eventually find it important to know the difference between a gallica and a Bourbon. But until that point, our advice is not to worry about it. The important thing is to select a rose that you find beautiful, and that suits your garden.
Pests and diseases: Prevention is the best way to avoid pest and disease problems. Start with disease-resistant varieties, keep plants in healthy condition (well fertilized and well watered), maintain good air circulation, keep foliage dry, and remove any diseased foliage or spent flowers. For Japanese beetle grubs, use beneficial nematodes or Milky Spore (Bacillus popilliae). Rose Rx is effective against scale, spidermites and aphids. For more information, see the Pest and Disease Finder.
It is generally agreed that "old roses" include species or wild roses; albas; Bourbons; moss roses; China roses; Noisettes; Portland roses; rugosa roses; Scotch roses; centifolias; hybrid pimpinellifolias; damasks; gallicas; hybrid perpetuals; tea roses; and musk roses. Those classified as modern rose varieties are hybrid teas; floribundas; polyanthas; grandifloras; miniatures and dwarfs; modern shrub and landscape roses; climbers and ramblers; and rugosa hybrids.
The Baggie Method: This was the first method I ever tried. Here you fill 2-inch plastic pots with potting soil, insert the rose stem halfway inside the pot, then put the pots into a one-gallon plastic zip-lock bag. You can get four 2-inch pots into each gallon bag. I didn't like this method because it caused many of the cuttings to rot since the bags tended to fold over and therefore prevented the air from circulating. The success rate of this method is not very good. It may be helpful to place a couple of small sticks inside the bag to help keep it upright and full of air.
Black Spot: Rose plant leaves with black spots that eventually turn yellow have black spot. This is often caused by water splashing on leaves, especially in rainy weather. Leaves may require a protective fungicide coating, which would start in the summer before leaf spots started until first frost. Thoroughly clean up debris in the fall, and prune out all diseased canes.