Rose thorns help their flowers drink water. When removing thorns from rose stems for flower arrangements, be careful not to damage the stem, so the flower arrangement will bloom to its fullest. You may use various methods to successfully and safely remove the thorns from the roses, including removal by hand (if you have many roses or thorns this method may be tedious), by using garden strippers (strips flowers of their leaves and thorns and available from most garden suppliers), or by using a small paring knife.
Wear heavy gloves to protect your hands from the thorns. Any sort of gardening glove will suffice, as long as the material is thick enough that you cannot be stuck by thorns.
Grasp the stem between your thumb and fingers at the top of the rose.
Pull your hand down, keeping your grasp tight but holding the stem gently enough to avoid damaging it. The thorns will strip off as you bring your hand down.
Garden Stripper Method
Hold the de-thorning strippers just below the flower.
Close the jaws of the strippers together around the stem, applying a little pressure but not so much that would result in damaging the stems.
Drag the de-thorning stripper down to remove the thorns. It may take a few tries to get the right pressure, so make sure to apply less pressure first and then a little bit more with each try so you ensure that you never apply too much pressure to damage the rose.
Paring Knife Method
Hold the head of the rose in the palm of your hand, careful not to squeeze the flower.
Place the edge of the knife parallel to the stem and scrape the thorns and leaves off, being careful not to damage the stem.
Repeat this motion as necessary. Ideally, the thorns and leaves will come off in one attempt, but if not repeat the above steps.