Q. Last May, I planted a white climbing rose. It produced a few white flowers last summer; this year, however, all the flowers are red. What happened?
A. When plants are difficult to grow from seeds or cuttings, they can be grown through a process called grafting. Most hybrid roses are grown by this method. In grafting, a small piece of the desired plant (scion) is spliced onto the roots (rootstock) of a very closely related plant. This means that the roots and shoots are different. After grafting, growth from the rootstocks is typically below ground, but occasionally they will produce an above-ground shoot. These errant shoots will reflect the genetics of the roots.
In your case, I would guess that a white rose was grafted onto the roots of a red rose; however, it also produced a red shoot from the crown of the roots. At some point, the white shoots of the plant must have been removed or they died, which left only the red portion of the plant to grow. You now have a red rose. If you would like a white rose, you will have to remove the red one and replant with a new white one.
Q. I would like some privacy in the back yard of my rowhouse, but I do not want to install a fence. Can you recommend any plants that will form a narrow hedge?
A. There are very few plants that naturally grow into a tall narrow form. So it is difficult to find plants that provide privacy without taking up a significant portion of rowhouse yard.
You will have to look for very specific cultivars that have been selected for their narrow columnar habit. For example, there are several narrow yews that could work, but be very careful when you choose. Most hedge yews spread mightily with age. Also, there are several very narrow Japanese hollies worth considering. I would recommend that you call several good nurseries to find out what they can offer you. You will probably have to do a little shopping to find exactly what you want.
1. Store unused seed in a cool, dry spot. Most seed is best kept within a sealed container in a refrigerator.
2. Mushrooms frequently emerge in beds and lawns after significant rains. They are best kept in check by knocking them down with a shovel or hoe.
3. Are you going away for extended periods this summer? Plan now to have someone to water your plants.
Dennis Bishop is an urban horticulture educator for the Baltimore office of the Maryland Cooperative Extension Services. If you have a gardening or pest problem, you can call the Home and Garden Information Center hot line (Monday through Friday, 8 a.m. to 1 p.m.) at 800-342-2507. You can also e-mail questions, order publications and diagnose plant problems by visiting the Web site, www.hgic.umd.edu.