Yes, it is possible to plant a rose stem and grow a new rose plant from it. This process is called "propagation" and can be done in a few different ways.

One common method is to take a stem cutting from an existing rose plant. This cutting should be about 6-8 inches long and should be taken from a healthy, disease-free section of the plant. Remove the leaves from the bottom of the stem, leaving only a few at the top, and then dip the cut end in rooting hormone. Plant the stem cutting in a pot filled with potting soil, making sure to keep the soil moist but not waterlogged. Place the pot in a sunny location and in a few weeks, you should see new growth.

Another method of propagating roses is called "layering." This involves bending a healthy stem from an existing rose plant down to the ground and covering a portion of it with soil. The buried section of the stem will begin to develop roots, and once it has established a good root system, it can be cut from the original plant and transplanted to a new location.

Regardless of the method you choose, it's important to choose a healthy, disease-free stem to ensure the best chances of success.