These openings, which are usually caused by stems rubbing against each other, are breeding grounds and entry spots for diseases. Creamy white or green, with no brown spots, is healthy. Brown or blackened wood is very old or dead and won't produce blooms. Fresh wood is much easier to cut than deadwood, and you'll learn to feel the difference with your shears. Multiple canes coming from a single bud union will vary in color by age.
New canes are often either quite red or a clean, healthy-looking green.
Older wood is darker, grey and more scaly. Some varieties make pruning easy for you by practically color coding their wood. Others produce wood of the same color, regardless of age, making pith examinations mandatory. Don't confuse the age of rosebushes with the age of the canes that form them. New canes are produced each year.