This article is designed to help you when you go to the nursery to buy a rose in one of those five gallon black plastic pots. I do not recommend buying "bare root" roses covered in wax. Buying bare root roses through the mail is fine. Just be sure you order them in January so you can plant them before March 1st.
Container roses, on the other hand, can be planted at any time. Of course, selection is best in January and February. Also, if you plant a container rose in the heat of our summer, be sure and water it twice a day for the first 7 to 10 days. And don't fertilize a newly planted rose until after the first set of blooms have appeared.
And now, how to buy a containerized rose.
Most of this article applies to hybrid tea and floribunda roses. Miniature roses are grown on their own roots. Just look for a healthy plant. Old garden roses are also grown on their own roots. They usually appear to be very tiny compared to other roses. Still, they usually do fine in spite of the size typically offered.
Hybrid teas and floribundas are another matter. These roses are grafted onto other root stock. They are more delicate. Choosing a particular plant is more critical.
What you are looking for is a plant with at least three good canes coming from the place where the type of rose you are buying has been grafted to a root stock suitable for this area. The spot where this graft occurs is called the bud union. The bud union appears as a big swelling just above the soil line. Make sure the canes come from the bud union. A big cane with branches just above the bud union is not what you want. The canes about which I am speaking should originate in the swollen area of the bud union itself.
Also, look at the spread of the canes. You want canes that angle out from the bud union. Stay away from canes that cross over or touch each other.
Ideally, you want the canes to be the diameter of a cigar. That the canes are only 8 to 12 inches long is just fine. However, if you see dieback at the end of a cane (a brown area at the tip), don't assume that cane will live.
Make sure the plant has a label on it so you can be sure you are getting the plant you want. And make out your shopping list before you go to the nursery. That way you will have a chance to select roses suitable for Houston before all that beauty tempts you into getting a plant less than suitable for our area or your experience.
If you join the Houston Rose Society you can get their list of recommended roses for Houston. The American Rose Society publishes a yearly Handbook for Selecting Roses that gives a numerical evaluation of each rose. Many of the nurseries and bookstore offer rose booklets that discuss selecting roses. I like the ones by Sunset and HP Books.
Also, consulting rosarians from the Houston Rose Society can be found at the better nurseries in town each spring. They will be happy to help you with your selections.
Happy rose growing.